Steel Rebar — 20 mm Nominal
The Schedule Is Measured. Will The Quotes Come Back Comparable?
A quantity surveyor reaching a 20 mm page is usually not asking whether the bar exists or what it weighs. The schedule has already been measured, the quantities are already in the bill, and the question is whether what you are about to send out will come back as a comparable price or as a list of clarifications. That depends on three things travelling with the enquiry: the shape codes, the cut lengths, and the units your counts are expressed in. Get those three wrong on a 20 mm package and you are not haggling over a small sum — this is the diameter that carries main bars in beams and columns, so a units error is counted in tonnes. The reconciliation below is built for exactly that check: you enter the schedule you hold, and it tells you what is ready to issue and what will come back.
What decides whether the enquiry works
- The unit your quantities are in — stated, not implied.
- Shapes conveyed by standard code, so every bidder prices the same bar.
- The detailing document named, so no bidder invents a bend basis.
Mass basis checked as of
Where This Size Sits
A main-bar diameter — which is why the paperwork has to be right before the price is
Size selection has been settled long before an enquiry reaches a distributor, but the role the diameter plays is what tells a quantity surveyor where the money actually sits. At 20 mm the bar is carrying member loads rather than holding stirrups together, so the quantities are large, the cut lengths are long, and a documentation gap costs more than it would on a small-diameter package. These cards are grouped by the situation you are in, and each states what the size does not settle as well as what it does.
20 mm nominal
This sizeReach for it when
Where the schedule calls a main bar for beams, columns or piles and the quantity is large enough that the mass basis and the schedule documentation both carry real money.
What it does not settle
The size fixes geometry and the nominal mass. It says nothing about grade, standard, coating, coupling method or whether the bar is adequate for the member.
16 mm nominal
Smaller adjacent sizeReach for it when
Where a member's schedule steps down a diameter and the enquiry spans both — common in a single beam or column schedule.
What it does not settle
Not a substitute for 20 mm. A different diameter changes the area, the mass basis and every bend, lap and anchorage provision referenced to it.
Open this route25 mm nominal
Larger adjacent sizeReach for it when
Where the schedule steps up for heavier loaded members, or where a design has consolidated two bars into one heavier bar.
What it does not settle
Not a substitute for 20 mm. Consolidating bars is a design decision with a detailing consequence, not a procurement swap.
Open this routeAll rebar sizes
Size indexReach for it when
When the enquiry spans several diameters and the question is how the sizes relate rather than what one size requires.
What it does not settle
An index, not a specification. The properties of any size still come from the governing standard and the grade your project selected.
Open this routeLong bars, large quantities
A 20 mm schedule is main bars in beams, columns and piles. Cut lengths run long and counts run high, so the tonnage is a real number and the mass basis under it never gets a second look until it matters.
Shaped more often than not
These bars are bent at ends, cranks and laps far more often than a stirrup schedule is. The shape has to travel in a form a fabricator can price without interpreting your drawing.
Documentation is the risk
The steel is rarely the problem. What goes wrong is an enquiry that assumes the bidder shares your reading of a unit, a shape or a detailing provision.
The reconciliation rule
Treat the diameter as geometry and the schedule as an instruction. The diameter fixes the nominal area and, with a stated density, the nominal mass per metre. Everything that decides whether a fabricator can actually cut the bar — the shape code, the cut length, the allowance, the bend and mandrel provisions — comes from documents that sit outside both the diameter and this page. Where a schedule steps from 20 mm to 16 mm or 25 mm, that is a design decision with a detailing consequence rather than a procurement swap, and re-issuing quantities on a different diameter without revisiting the detailing is how a comparable enquiry becomes an argument.
20 mm Schedule Reconciliation
Check the schedule is issueable before you send it out
Enter the unit your counts are in, how the shapes are conveyed, where the cut lengths come from and which document supplies the bend provisions. The reconciliation tells you whether an enquiry built on this schedule will come back as comparable prices or as a round of technical queries — and it reports the nominal mass on a basis you can reproduce. It does not compute a bend allowance, and it will not invent a shape code, a cut length or a quantity you have not supplied.
How the schedule is documented
Required fields marked *The single most common cause of non-comparable prices. State it on the enquiry itself.
A standard shape code and a sketch are different comparison bases, not different spellings of the same one.
An approved schedule is a requirement. A take-off is an estimate that transfers an allowance decision.
This page will not supply a bend or mandrel value — it will tell you if you have not named the document that does.
Quantities (optional — needed for the mass figure)
Run each distinct cut length separately. Blending several lengths into one average is where a tonnage discrepancy hides — this page will not do it for you.
The mass formula, printed
area = π × (20 ÷ 2)² = 314 mm² → area in m² = 314 ÷ 1,000,000
nominal mass per metre = area (m²) × 7,850 kg/m³ = 2.466 kg/m
estimated mass = nominal mass per metre × cut length × piece count
Density basis: 7,850 kg/m³ (standard steel density convention). The area is geometry from the nominal diameter, stated so you can verify it on a calculator. Every result is labelled theoretical and nominal.
Documents to request with this consignment
This reconciliation does not return a bend allowance, a lap length, an anchorage length, a bend or mandrel diameter, or any structural capacity. It does not check your schedule against the drawings and cannot detect a superseded revision.
Reconciliation status
Start with the unit and how the shapes are described
These two answer the question a bidder asks first, and they are the two the enquiry most often leaves out. The unit tells a fabricator what your count means; the shape description tells them what they are being asked to produce. Select both and the rest of the reconciliation follows — including what is still missing.
Basis of this figure
Nominal mass basis: cross-sectional area from the nominal 20 mm diameter (area = π × (d/2)²), multiplied by cut length and piece count, at 7,850 kg/m³ (standard steel density convention). Theoretical and nominal — not a weighbridge result, not acceptance evidence.
Still to settle
- The revision of the schedule being issued, and confirmation it is the approved one.
- The unit your counts are expressed in, stated on the enquiry itself.
- The document and edition supplying the bend, mandrel and hook provisions.
- The splice or lap regime, which is a design decision rather than a fabrication one.
- Whether the enquiry is for cut-and-bent bar or for stock lengths cut on site.
Boundaries of this reconciliation
- This reconciliation does not return a bend allowance, an allowance for fabrication, a lap length, an anchorage length or a bend diameter. Those depend on the governing standard, the grade, the concrete, the cover and the member, and they are not derivable from a diameter or from a schedule row.
- The mass returned is a theoretical nominal figure. The commercial weighed mass of a consignment and its permitted tolerance are separate records, established by the quotation and the printed standard respectively.
- It does not assess whether a shape is physically producible on a given bender, whether a bend sequence suits the fabricator's tooling, or whether a cut length fits a transport or lifting constraint.
- It does not reconcile your schedule against the drawings, does not detect a superseded revision, and does not verify that the quantities in your bill match the schedule you are issuing.
- Where the schedule describes shapes by sketch rather than by a standard shape code, the comparison between bidders is inherently weaker, and no reconciliation output changes that.
Nothing is transmitted from this panel. Once the schedule revision, the unit and the detailing basis are settled, send the summary to the commercial department so the offer is built on a fixed basis.
Shape Codes & Cut Lengths
Four inputs that decide whether a bidder can price your schedule
A bar schedule is an instruction, and an instruction only works if it is unambiguous. The four inputs below are the ones that most often go missing between a quantity surveyor's measurement and a fabricator's quote. The table states what each one does to the comparison, and the action that closes it. No bend, lap or allowance value is published anywhere on this page.
| What the enquiry must state | What happens when it is missing | Where the answer comes from | Action to close it |
|---|---|---|---|
| The unit the quantities are in | Each bidder reads the bare number the way that suits their pricing. Bars, members and tonnes share numerals and mean different things. | Your measurement, and the basis your bill was built on. | Write the unit on the enquiry itself, not only in the schedule. |
| The shape of every bent bar | Every bidder re-derives the shape. Differences in their reading become differences in price, and the lowest bid may simply be the loosest reading. | The governing bar schedule standard supplies the shape codes. | Convert sketches to standard shape codes before issuing. |
| The cut length, per piece | Bidders apply their own allowance to your measured length. Two bidders, two allowances, two prices for the same bar. | The approved bar bending schedule at its stated revision. | Issue the schedule revision with the enquiry. |
| The bend and mandrel provisions | Each bidder assumes their own detailing practice, and none of them is wrong — they are just different from each other. | The printed standard in the cited edition, or the project's own detailing provisions. | Name the document and edition, or record it as open. |
| The schedule revision | Two bidders quote against different revisions, and neither price matches the drawing you hold. | Your document control register. | State the revision on the enquiry and in the summary. |
| The splice or lap regime | A design decision migrates into the fabrication price, where it is invisible and unexamined. | The project's design authority and detailing code. | Keep it on the design record; state it if the enquiry depends on it. |
Rows are separated by the document that answers them, not to compare values. Confirm every shape code, allowance, bend, mandrel and tolerance figure against the printed standard and your project's own schedule before issuing an enquiry. No such value is published on this page.
Why it lands on the QS
The gap opens between measuring the work and issuing the enquiry
By the time a 20 mm package is measured, the hard part is already done: the quantities are in the bill and the drawings have been interrogated. What sits between that point and a price is not more measurement — it is the translation of what you measured into something a fabricator can cut. That translation is where the unit gets dropped, the sketch replaces the code, and the allowance becomes implicit. None of those is a measurement error, and none of them is visible in the quantity itself, which is precisely why they survive until the quotes come back and nobody can explain the spread.
The reconciliation above is deliberately built to catch this class of problem rather than to price the steel. It cannot see your drawings, and it makes no claim to. What it does is hold you to stating the four inputs that a bidder needs, and report back plainly when one of them is an estimate dressed as a requirement — which is the point at which an enquiry is still cheap to fix.
Mass & Tolerance Evidence
Three masses and two length sets — which one is on your enquiry?
A 20 mm package generates more numerical bases than a small-diameter one, and at this size they carry real money. The table separates them, states which document governs each, and names the action that keeps them from being conflated between the enquiry, the quotation and the invoice.
| Record | What it actually is | Governed by | Enquiry action |
|---|---|---|---|
| Theoretical nominal mass | A figure derived from nominal area and a stated density. Supports estimating and comparison between bids. Not a measurement of anything. | The formula you apply, and the density you state. | Print the basis with the figure so bids are comparable. |
| Commercial weighed mass | The mass the consignment is bought and invoiced on, established by an agreed weighing method. | The quotation and contract terms. | State the weighing basis and tolerance in the quotation. |
| Permitted dimensional tolerance | How far the actual bar may deviate from nominal dimension and mass. | The printed standard, in the edition your project cites. | Read it from the standard before the receiving check. |
| Nominal cut length | The length the schedule calls for, before any allowance decision is applied to it. | The approved bar bending schedule at its revision. | Issue the revision; do not let a bidder infer it. |
| Ordered cut length | The length actually produced, after the fabricator applies an allowance. | The fabricator's method, within the detailing provisions. | Reconcile against the schedule before award. |
| Mill test certificate for the heat | The material in the heat it was tested from, in the terms the standard your order names requires. | The delivering mill, against the named standard. | State the standard and edition it is read against. |
| Dimensional verification record | What physically arrived, checked against the permitted deviation on the actual bar. | Your project's receiving inspection. | Agree the basis before delivery, not after. |
Nominal is not weighed
A figure derived from a density and a stated weighing basis are different bases. Compare them only with the tolerance and the method shown, never as though one number served both.
Tolerance is a standard question
The permitted deviation on the actual bar comes from the printed standard and edition. It is not something an estimating figure can carry, and not something a page can supply.
Two lengths, one difference
The length the schedule calls for and the length that has to be cut to satisfy it differ by an allowance decision. Whoever applies that decision owns the difference.
Rebar weight calculator
Run the mass figure across a schedule that spans several diameters, using an input basis you supply rather than one this page assumes.
Open technical referenceRebar sizes
Check how the nominal diameters relate before the schedule's size call-outs are taken as read across the whole package.
Open technical reference
Where The Diameter Works
Three settings where a main-bar schedule carries real money
These are the application settings where 20 mm is most often specified and where the reconciliation above carries the most weight — not because the steel behaves differently, but because the quantities are large, the bars are shaped, and the documentation gap between a measured schedule and an issued enquiry is measured in tonnes.
Concrete reinforcement bar
Why the reconciliation matters here
The core role, and where a 20 mm bar does its heaviest work as a main bar in beams, columns and piled foundations — the members where a quantity error is counted in tonnes rather than pieces.
Fit limit
Which diameter belongs in which member is a design decision from your drawings and specification, confirmed against them rather than inferred from the size.
Open applicationPrecast concrete rebar
Why the reconciliation matters here
Precast beds are repetitive and mould-driven, so a main bar is usually a cage or mattress assembly rather than loose bar — which pushes the enquiry from material supply into fabrication.
Fit limit
Element type, lifting design and mould geometry come from your project; the size citation does not settle them.
Open applicationBridge rebar
Why the reconciliation matters here
Bridge decks and piers use heavy main bars under strict line-and-level control, and they frequently layer project-specific detailing provisions over the standard your schedule cites.
Fit limit
The bridge's governing design code, fatigue requirements and exposure class are assessed against the project, not inferred from the bar size.
Open applicationApplication fit is confirmed against the standard and edition your project cites, the grade and delivery condition specified, and the project's own design rules when the enquiry is quoted. No generic or unsupported suitability claims are made on this page.
GCC Markets & Destination Planning
Fix the destination basis before the schedule goes out
For each GCC destination the specification, document set and commercial terms are aligned to your project basis at quotation. Because a 20 mm package is a fabrication enquiry as much as a material one, aligning the destination and document basis across sources is what makes the offers comparable rather than merely similar on price.
United Arab Emirates
Import documentation and certificate review.
Add the delivery location, importer and customs inputs, Incoterm and required document set before the 20 mm enquiry is issued.
Saudi Arabia
Large project packages and cross-border documentation.
Confirm destination, importer inputs, Incoterm and documents so a scheduled main-bar quantity is quoted on one consistent basis.
Qatar
Technical submittal readiness for infrastructure.
State the submittal and certificate package the project requires for the standard and edition your schedule names.
Kuwait
Contractor and fabricator hand-off.
Provide delivery location, Incoterm, documents and required date so the cut-and-bent order can be planned against the schedule.
Bahrain
Contractor procurement and industrial supply.
Provide destination, importer and customs inputs, Incoterm and documents before the 20 mm quotation is prepared.
Oman
Port-oriented project supply planning.
Confirm the destination, required documents and Incoterm so the quotation basis is fixed for the size and standard cited.
Destination, documents, port or delivery line, Incoterm and the required delivery date are fixed at quotation from your specification. No served markets, local stock, local branches or delivery times are claimed in advance.
Verifiable Outcomes
Each concern mapped to the check on this page, then to what you can rely on
No superiority claims. Each row names a specific risk on a main-bar enquiry, the mechanism on this page that addresses it, and the practical outcome that follows.
| Buyer concern | Check on this page | Outcome you can rely on |
|---|---|---|
| An unlabelled quantity on the enquiry | The unit the count is expressed in is a required input, and the reconciliation reports it back on the summary. | Bidders price the same instruction rather than assuming a reading. |
| Shapes a bidder must interpret | The shape description is a required input, and prose or sketch form is reported as a weaker comparison basis. | A difference in price reflects the work, not the reading. |
| Estimating lengths issued as a fabrication enquiry | Approved schedule, take-off and measured quantities are separate sources returning different results. | The allowance decision stays with the project that owns it. |
| A bend basis nobody has named | The detailing document is a required input, and an unnamed or open basis flags the result. | A round of technical queries is pre-empted rather than absorbed. |
| A tonnage with no visible derivation | The reconciliation prints its formula, its density and its nominal area beside the figure. | A quantity anyone reviewing the enquiry can reproduce and audit. |
| A non-numeric quantity quietly rounded | A piece count or cut length that is not a positive number blocks the figure instead of being adjusted. | No tonnage is emitted that the schedule never supported. |
From schedule to delivery
- 1
Fix the schedule revision and the unit
Confirm the schedule you are issuing is the approved revision, and state whether the counts are bars, members, linear metres or tonnes. Both travel on the enquiry.
- Owner:
- Quantity surveyor
- Input:
- Approved bar bending schedule
- Output:
- Fixed revision and stated unit
- Risk:
- A superseded revision or an unlabelled quantity
Next: Confirm the shapes are coded
- 2
Confirm the shapes are coded
Check that every bent bar carries a standard shape code rather than a sketch, because coded shapes are what makes two bidders price the same requirement.
- Owner:
- Detailer + QS
- Input:
- Bar bending schedule, shape codes
- Output:
- Shapes described in a priceable form
- Risk:
- Sketch-only shapes priced differently by each bidder
Next: Name the detailing basis
- 3
Name the detailing basis
State the document and edition that supplies the bend, mandrel and hook provisions, since at this diameter the detailing provisions sit outside the schedule that calls the bar.
- Owner:
- Design authority
- Input:
- Governing standard, project specification
- Output:
- Detailing document identified
- Risk:
- Each bidder assuming their own bend practice
Next: Establish the mass basis
- 4
Establish the mass basis
Compute the tonnage from nominal area, a stated density and your cut lengths, and keep it labelled theoretical so it is never read as the weighed commercial mass.
- Owner:
- Quantity surveyor
- Input:
- Cut lengths, counts, nominal area
- Output:
- Reproducible mass estimate
- Risk:
- Theoretical and weighed mass conflated
Next: Fix the weighing and evidence route
- 5
Fix the weighing and evidence route
Decide how the commercial mass is established and what the consignment arrives with, so the enquiry, the quotation and the invoice rest on one stated basis.
- Owner:
- Buyer + commercial
- Input:
- Inspection plan, certificate requirement
- Output:
- Evidence route assigned
- Risk:
- Tolerance and weighing basis left implicit
Next: Issue the qualified RFQ
Technical reference note
Where the one figure on this page comes from, and where it stops
A source-backed note on the nominal mass basis, stated with its formula, its density and its limits.
The figure, and the three things it is not
A nominal round bar's cross-sectional area follows from its nominal diameter by geometry alone: area = π × (d/2)². At a nominal 20 mm that gives approximately 314 mm². Multiply that area, converted to square metres, by the standard steel density convention of 7,850 kg/m³ and you reach approximately 2.466 kg per metre. The chain is reproducible on a calculator, which is the point — a quantity surveyor can verify it, and anyone reviewing the enquiry can trace it to two inputs rather than to a table of unknown provenance.
What the figure is not is a measurement, and it is not the basis of a commercial agreement. It is theoretical and nominal by construction, so it supports estimating and comparison but cannot stand in for the weighed mass of a consignment, for the permitted dimensional and mass tolerance on the actual bar, or for what physically arrives. Those are three separate records with three separate owners, and this page keeps them apart on purpose. It also declines the values it cannot source: no bend allowance, lap length, anchorage length, bend diameter or mandrel size appears anywhere here, because none of them follows from a diameter or from a schedule row.
Primary authority
The nominal-diameter geometry and the steel density convention of 7,850 kg/m³ are stated so the derivation can be reproduced. The permitted tolerances on dimension and mass, the shape codes used to specify bent bars, the bend and mandrel provisions, and the acceptance requirements for the reinforcement itself are set by the standard your project cites and by its edition — consult the printed standard, or your project specification's citation of it, rather than a nominal figure.
Mass basis checked · confirm tolerances, shape codes and detailing provisions against the printed standard before issuing an enquiry
What this note does and does not cover
Covers: the nominal area of a round 20 mm bar from its nominal diameter, the density convention applied to it, and the resulting nominal mass per metre — with the derivation printed so it can be reproduced and audited.
Does not cover: bend allowances, lap and anchorage lengths, bend and mandrel diameters, shape code definitions, permitted tolerances, the structural adequacy of the bar in any member, or the commercial weighing basis. Each comes from the printed standard, the project's drawings, or the quotation.
Limit: a nominal figure supports estimating and comparison between bids. It is not acceptance evidence, it is not a weighbridge result, and it does not verify what physically arrived.
Practical consequence: issue a fixed schedule revision, state the unit your quantities are in, convey shapes by standard code, name the detailing document, and keep the weighed mass and its tolerance as a separate commercial record.
FAQ
What a quantity surveyor asks before issuing a 20 mm enquiry
Written for the schedule and documentation decisions that have to be right before a main-bar package can be priced comparably.
What is the nominal mass of 20 mm rebar per metre?
A nominal 20 mm round bar has a nominal cross-sectional area of about 314 mm², and at the standard steel density convention of 7,850 kg/m³ that gives a nominal mass of approximately 2.466 kg/m. The basis matters more than the figure here, because at this diameter it multiplies quickly — a small error in the assumed mass per metre becomes a large error in a tonnage. That is why the reconciliation on this page prints its formula, its density and the nominal area beside every figure, so the number can be reproduced and checked rather than trusted. It remains a theoretical nominal value, not a weighbridge result.
Why does the unit my quantities are in matter so much?
Because a fabricator cannot cut anything from a number they have to interpret. A count of bars, a count of members and a figure in tonnes are three different instructions that happen to share the same numerals. If the unit is not stated, each bidder reads it the way that suits their pricing, and the prices you receive differ by more than the work does — which defeats the purpose of going out to several suppliers at all. Stating the unit on the enquiry is a one-line fix for what is otherwise a slow, expensive comparison problem.
Can this page work out the bend allowance for me?
No, and it will not guess at one. A bend allowance depends on the governing standard's provisions, the grade, the delivery condition and the fabricator's method, and a difference in allowance changes the cut length you need to order. If a page invented a figure, the error would propagate silently through every piece on the schedule, and at 20 mm it would be measured in tonnes. What this page does instead is require you to name the document that supplies those provisions, and flag the enquiry when it has not been named.
We usually describe shapes on the drawing rather than by code — is that a problem?
It is a comparison problem rather than an error. Sketches convey the shape, and a good fabricator will produce it. But every bidder re-derives the shape from the sketch, and their individual readings become individual prices. Arbitration clauses exist because that is exactly what happens. Using standard shape codes means every bidder is working from the same unambiguous instruction, so the prices that come back differ by their productivity and material cost rather than by their reading of your drawing.
How do I check the tonnage in my bill against the schedule?
The check is that the total linear metres implied by your schedule divides cleanly into your cut lengths. Take the piece count at each cut length — not one blended average — multiply out, and confirm the total metres matches what your bill was measured on. A remainder means a piece you will be short of. Then apply the nominal mass per metre on a stated basis and compare. This page reports the derived per-piece figures so the arithmetic is visible; it deliberately does not blend multiple cut lengths into one average, because that blend is where the discrepancy hides.
What should accompany the enquiry so the quotes come back comparable?
Four things, and the reconciliation above will tell you which are missing. The approved schedule revision you are issuing against. The unit your quantities are expressed in. Shapes conveyed by standard code rather than by sketch. And the document and edition that supply the bend, mandrel and hook provisions. Where any of those is absent, a bidder fills the gap with an assumption, and assumptions are what make two quotations for identical steel differ by a margin nobody can explain afterwards.
Qualified RFQ
Request a quote for 20 mm Rebar
Copy the reconciliation summary you have built, then send it to the commercial department. The enquiry is ready for review once the unit, the shape basis, the cut-length source and the detailing document are stated.
Price, stock, origin and lead time remain quotation-dependent unless current verified evidence is present. The mass figure above is theoretical and nominal, and does not represent the weighed commercial mass of a shipment.
Office 3303, Churchill Executive Tower, Business Bay, Dubai, United Arab Emirates
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Copyable reconciliation summary
- Unit of count
- Not stated
- Shape description
- Not stated
- Cut-length basis
- Not stated
- Detailing basis
- Not stated
- Schedule revision
- Not stated
- Pieces
- To be confirmed
- Cut length
- To be confirmed
- Destination
- To be confirmed
Add any remaining open items — the weighing basis, required documents, availability, price or lead time — as explicit fields before sending.