Steel Rebar — 8 mm Nominal
Thousands Of Bent Pieces, One Diameter — Get The Basis Right
A nominal 8 mm bar is the smallest diameter most reinforcement schedules actually buy, and it is almost never the bar carrying the load. It turns up as stirrups and links in beams and columns, as ties, as distribution steel in a slab, and as the light reinforcement in a precast element. That single fact sets the whole purchasing problem: you are ordering a very large number of short, repeatedly-bent pieces rather than a modest count of long straight ones. So the quantities that matter are piece counts and cut lengths, the risk sits in the bend and hook details rather than in the tonnage, and the mass figure your estimate rests on has to come from a nominal basis you can name — because at this diameter, a wrong assumption inside a formula gets multiplied by thousands of pieces before anyone notices.
What actually decides this order
- Piece counts and cut lengths drive the quantity — not tonnage.
- The bend and hook basis decides whether the cut length is right.
- Nominal mass is a named formula, never an unsourced weight per metre.
Mass basis checked as of
Where This Size Fits
When the schedule reaches for 8 mm, and when it is the wrong answer
Size selection is a detailing decision that has already been made by the time an enquiry reaches a distributor — but it is worth reading why, because the role the diameter plays is what tells you which quantities matter and where the risk sits. The cards below are grouped by the situation you are in rather than alphabetically, and each one states what the size does not settle as well as what it does.
8 mm nominal
This sizeReach for it when
When the schedule calls a small nominal diameter for stirrups, links, ties, distribution steel or a light precast element, and the quantity is measured in piece counts rather than tonnes.
What it does not settle
The size fixes geometry. It says nothing about grade, standard, coating or whether the bar is adequate for a structural role — those are separate decisions.
10 mm nominal
Adjacent sizeReach for it when
Where the schedule steps up a diameter for the same class of work, or where a design has consolidated two small diameters into one.
What it does not settle
Not a substitute for 8 mm. A different nominal diameter changes the area, the mass per metre and every bend and lap provision referenced to diameter.
Open this route12 mm nominal
Adjacent sizeReach for it when
Where the small-diameter work has been designed out and the schedule consolidates onto a single heavier bar for the same member.
What it does not settle
Not a substitute for 8 mm. Substituting a diameter changes the detailing, the cover relationship and the mass basis, and it is a design decision rather than a procurement one.
Open this routeAll rebar sizes
Size indexReach for it when
When the schedule spans several diameters and the question is how the sizes relate rather than what this 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 route
Count, not tonnage
An 8 mm package is measured in pieces and cut lengths. A per-piece error is repeated across the whole order, so the quantity basis matters more than the margin on any one bar.
Bends, not strength
The bar is rarely the structural question. What it has to be is bent to a repeatable, tightly specified shape — so the bend and hook provisions carry the risk.
Nominal, not weighed
The mass figure behind an estimate is geometry multiplied by a stated density. It supports estimating and is not a substitute for the weighed commercial mass.
The sizing rule
Treat the diameter as geometry and nothing more. It fixes the nominal area and, with a stated density, the nominal mass per metre. It does not fix the grade, the standard, the delivery condition, the coating, the bend provisions or whether the bar is adequate for a role. Where a schedule moves from 8 mm to 10 mm or 12 mm, that is a detailing decision with a design basis behind it — it is not an equivalent substitution, and re-running a takeoff on a different diameter without revisiting the detailing is how a workable order becomes a rework.
8 mm Takeoff Checker
Turn a cut list into a mass estimate you can actually audit
Enter the piece count and the cut length you intend to order, and this checker returns a theoretical nominal mass with its formula, its density and the nominal area printed beside it — so you can reproduce the figure on a calculator and whoever reviews the enquiry can check it. It will not compute without both quantities, it will not round a non-numeric input into something plausible, and it returns no lap, bend, mandrel or capacity value at all.
Cut list & basis
Required fields marked *How many pieces at this cut length. Run each distinct length separately.
The length you intend to order — not the dimension you measured off the drawing.
An approved schedule and a proposal are treated as different bases, because they are.
Leaving this unconfirmed flags the result rather than passing it.
The formula this checker uses
area = π × (8 ÷ 2)² = 50.3 mm² → area in m² = 50.3 ÷ 1,000,000
nominal mass per metre = area (m²) × 7,850 kg/m³ = 0.395 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. Every result is labelled theoretical and nominal.
Documents you want with this consignment
This checker does not return a lap length, an anchorage length, a bend diameter, a mandrel size, a hook dimension or any structural capacity. Those depend on the governing standard, the concrete, the grade, the cover and the member — none of which a diameter supplies.
Takeoff status
Enter the piece count and the cut length to begin
These are the two inputs that actually drive a small-diameter takeoff. At 8 mm the tonnage is rarely the difficulty — the piece count and the cut length are, because an error in either is multiplied across thousands of identical pieces before anyone catches it. Enter both and the estimated nominal mass follows immediately.
Basis of this figure
Estimate basis: nominal cross-sectional area from the nominal diameter (area = π × (d/2)²), multiplied by the cut length and the piece count, at a density of 7,850 kg/m³ (standard steel density convention). This is a theoretical nominal mass — it is not a weighbridge figure and not acceptance evidence.
Still to settle
- The approved revision of the bar bending schedule, if one exists.
- The document and edition that supplies the bend, hook and anchorage provisions.
- The splice or lap regime, which is a design decision rather than a material one.
- Whether the bar is being bought cut-and-bent or as stock lengths to be cut on site.
- How the commercial mass will be established and weighed, and against what tolerance.
Boundaries of this checker
- The mass returned is theoretical and nominal. It is not the commercial weighed mass of a shipment, and the permitted tolerance band on the actual bar is a separate figure read from the printed standard.
- This checker does not return a lap length, an anchorage length, a bend diameter, a mandrel size or a hook dimension. Those depend on the governing standard, the concrete, the grade and the cover, and they are not derivable from a diameter alone.
- This checker does not assess structural capacity, utilisation, spacing compliance or whether a given bar is adequate for a design. No diameter carries a capacity in isolation.
- Nominal area is geometry. A nominal 8 mm bar's actual dimensions and their permitted deviation are controlled by the governing standard, and a nominal-diameter calculation is not a substitute for a dimensional check.
- Where the cut lengths come from a drawing take-off rather than an approved schedule, every length carries an unstated allowance decision and the estimate inherits it.
Nothing is transmitted from this panel. Once the cut lengths, the bend basis and the document set are settled, send the summary to the commercial department so the offer is built on a fixed basis.
Pass & Bend Limits
The detailing questions a diameter cannot answer — and who does
At 8 mm the bar is bent more times per tonne than at any other size, so the provisions that govern bending matter more here than the material properties do. This table separates the questions that get folded into a single word like detailing, states which document answers each, and names the action that closes it. No bend, lap, mandrel or cover value is published on this page.
| The detailing question | What it actually depends on | Document that answers it | Action to close it |
|---|---|---|---|
| How tightly can this bar be bent? | The governing standard sets bend and mandrel provisions, and they are referenced to the bar rather than to a project preference. Delivery condition matters too. | The printed standard your project names, in the cited edition. | Name the document and edition before the schedule is issued. |
| How long must a lap be? | Grade, concrete strength, cover, bar position in the member and the detailing code adopted by the project. All five, together. | The project's detailing code and design drawings. | Take it from the design, never from the bar size. |
| How long must an anchorage be? | The same inputs as a lap, plus the shape of the anchorage and what it is resisting. | The project's detailing code and design drawings. | Design-side decision; record it on the schedule. |
| How much cover is required? | Exposure class, member type and fire requirements — not the diameter. | The project specification and the relevant code. | Fixed by the project; the diameter only enters through a bend constraint. |
| How much does the bar weigh? | Nominal area from the nominal diameter, multiplied by a stated density. That is the whole basis. | The formula on this page, referred back to the standard for tolerance. | State the basis with the enquiry so offers are comparable. |
| What tolerance is permitted on the bar? | The governing standard sets the permitted deviation on the actual dimensions and mass. | The printed standard, in the cited edition. | Read it from the standard before the dimensional check. |
Rows are separated by which authority answers them, not to compare values. Confirm every bend, lap, anchorage, cover and tolerance figure against the printed standard and your project's own drawings before detailing or ordering. No such value is published on this page.
Why it lands here
A bend error is cheap to fix on paper and expensive to fix in steel
When a small diameter is detailed wrongly, nothing about the material is wrong. The steel meets the grade, the certificate is genuine, and the consignment is exactly what was ordered. It is simply cut and bent to a shape the structure cannot use, and it arrives in the quantities a stirrup schedule produces — hundreds or thousands of pieces at once. That is why the bend basis is treated as a required input in the checker above rather than an optional note: on this diameter, the detailing provisions are the part of the order most likely to be assumed rather than read, and the assumption is the expensive part.
There is also a boundary worth stating plainly. None of these values can be derived from a diameter, so no distributor — this one included — can supply them for you. What a distributor can do is quote against the basis you have fixed, and tell you when the basis you have stated is internally inconsistent. That is the point at which an enquiry becomes useful rather than merely quick.
Mass & Cut-List Evidence
Which number is which, and what actually arrives with the delivery
A small-diameter order generates two masses and two length sets that are easy to conflate, and conflating them is how a quotation and an invoice end up disagreeing. The table below separates them, states who holds each record, and names the action that keeps them reconciled.
| Record | What it actually is | Who holds it | Enquiry action |
|---|---|---|---|
| Theoretical nominal mass | Exceptional figure derived from nominal area and a stated density. Supports estimating and comparison. Not a measurement. | Whoever built the estimate | Print the formula and density with the figure. |
| Commercial weighed mass | The mass the consignment is bought and invoiced on, established by an agreed weighing method. | The commercial agreement | State the weighing basis and tolerance in the quotation. |
| Nominal cut length | The length the schedule calls for, before any allowance decision is applied. | The project's detailer | Read from the approved schedule revision, not from a proposal. |
| Ordered cut length | The length actually produced, after any allowance or fabrication adjustment. | The fabricator | Reconcile against the schedule before the order is placed. |
| 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 | State the standard and edition it is to be read against. |
| Dimensional verification record | What physically arrived, checked against the permitted deviations in the printed standard. | Your project's receiving inspection | Agree the basis before delivery, not after. |
| Cut-and-bend fabrication records | That bending was performed to a specified procedure, where the supply form includes fabrication. | The fabricator or cut-and-bend shop | Request where fabrication is part of the order. |
Two masses, never one
A nominal estimating figure and a weighed commercial figure are different bases. Compare them only with the tolerance and the weighing method stated.
Two length sets, never one
The length the schedule calls for and the length that has to be cut to satisfy it are not the same figure, and the difference is an allowance decision.
Tolerance is a standard question
The permitted deviation on the actual bar comes from the printed standard and edition. It is not something an estimate can carry.
Rebar weight calculator
Run the mass figure for a schedule that spans several diameters, using an input basis you supply rather than one this page assumes.
Open technical referenceRebar weight chart
Check the nominal mass basis your tonnage was estimated on, and keep it consistent with the standard and edition your order names.
Open technical reference
Where The Diameter Works
Three settings where a small nominal diameter carries real risk
These are the application settings where 8 mm is most often specified and where the takeoff questions above carry the most commercial weight — not because the steel behaves differently, but because the piece counts are high, the bends are repetitive and the detailing provisions are frequently assumed rather than read.
Concrete reinforcement bar
Why the takeoff matters here
The core reinforcement role, and the one where the small diameters do most of their work — stirrups, links and distribution steel rather than main bars.
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 takeoff matters here
Precast beds are repetitive and mould-driven, so a small diameter appears as a high count of identical, tightly specified bent pieces — exactly where a bend-basis error is most expensive.
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 takeoff matters here
Bridge work uses small diameters for stirrups and distribution steel under strict line-and-level control, and it frequently layers project-specific detailing provisions over the standard.
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 cut-and-bend enquiry is issued
For each GCC destination the specification, document set and commercial terms are aligned to your project basis at quotation. Because a small-diameter order is a fabrication package as much as a material supply, 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 8 mm enquiry is issued.
Saudi Arabia
Large project packages and cross-border documentation.
Confirm destination, importer inputs, Incoterm and documents so a schedule-specified small diameter 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 8 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 small-diameter takeoff, 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 |
|---|---|---|
| A mass figure with no stated basis | Every estimate prints its formula, its density and the nominal area it used, and none is supplied from a table this page cannot cite. | An estimating number anyone reviewing the enquiry can reproduce. |
| A bend allowance applied to the wrong length | The bend basis is a separate required input, and an unconfirmed one flags the result rather than passing it. | The gap is visible while it is still cheap, not at goods-in. |
| Cut lengths taken from a proposal | A supplier cut-and-bend proposal is treated as a distinct source and returns its own flag. | The project's requirement is reconciled against the proposal before ordering. |
| Ordering a diameter against a per-piece figure | The checker will not produce a result without both the count and the cut length. | Quantities reach the enquiry in the form an estimator can add up. |
| Non-numeric input silently corrected | A piece count or length that is not a positive number blocks the calculation rather than being rounded. | No figure is emitted that the input never supported. |
| Treating an estimate as acceptance data | Theoretical nominal mass and commercial weighed mass are kept as separate records on every result. | The quotation states its weighing basis rather than inheriting an assumption. |
From cut list to delivery
- 1
Take the cut list from a fixed revision
Work from the approved bar bending schedule and record its revision, or state clearly that the lengths are an estimator's take-off so the basis travels with the figure.
- Owner:
- Estimator
- Input:
- Bar bending schedule, drawings
- Output:
- Cut lengths and counts at a named revision
- Risk:
- Working from a superseded revision
Next: Establish the bend and hook basis
- 2
Establish the bend, hook and anchorage basis
Name the document and edition that supplies the bend provisions, because at this diameter the bend detail, not the tonnage, is what decides whether the cut length is right.
- Owner:
- Design authority + detailer
- Input:
- Governing standard, project specification
- Output:
- Bend basis identified
- Risk:
- Bend allowance assumed rather than read
Next: Compute the estimate on a stated basis
- 3
Compute the estimate on a stated basis
Run the quantities through a mass figure whose formula, density and nominal area are printed beside it, so the number can be checked rather than trusted.
- Owner:
- Estimator
- Input:
- Cut lengths, counts, nominal area
- Output:
- Reproducible mass estimate
- Risk:
- A weight per metre nobody can source
Next: Decide cut-and-bent or stock lengths
- 4
Decide cut-and-bent or stock lengths
Small diameters are usually bought cut and bent, which moves the fabrication evidence to a different party and adds a step to the delivery plan.
- Owner:
- Buyer + fabricator
- Input:
- Fabrication capability, site capacity
- Output:
- Supply form fixed
- Risk:
- Fabrication responsibility left unassigned
Next: Fix the weighing and evidence basis
- 5
Fix the weighing and evidence basis
State how the commercial mass will be established and what the consignment arrives with, so the estimate and the invoice are not two different conversations.
- Owner:
- Buyer + commercial
- Input:
- Inspection plan, certificate requirement
- Output:
- Evidence route assigned
- Risk:
- Theoretical and weighed mass conflated
Next: Issue the qualified RFQ
Technical reference note
Why this page states a mass basis instead of publishing a weight table
A source-backed note on the one figure this page does produce, stated with its formula, its density and its limits.
The number, and exactly where it comes from
A nominal round bar's cross-sectional area follows from its nominal diameter by geometry alone: area = π × (d/2)². At a nominal 8 mm that gives approximately 50.3 mm². Multiply that area, converted to square metres, by the standard steel density convention of 7,850 kg/m³ and you arrive at approximately 0.395 kg per metre as a nominal figure. Every part of that chain is reproducible on a calculator, which is the point — an estimator can check it, and a reviewer can trace it back to two inputs rather than to a table of unknown provenance.
What the figure is not is a measurement. It is theoretical and nominal by construction. The commercial mass of the consignment is established by an agreed weighing method and carries a tolerance; the permitted deviation on the actual bar's dimensions comes from the printed standard in the edition your project cites. Those are three separate records, and this page keeps them separate on purpose. It also declines to publish the values it cannot source — no lap length, anchorage length, bend diameter, mandrel size or hook dimension appears anywhere on this page, because none of them follows from a diameter.
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 dimensional and mass tolerances, 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 and detailing provisions against the printed standard before ordering
What this note does and does not cover
Covers: the nominal area of a round 8 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.
Does not cover: lap, anchorage, bend, mandrel, hook or cover values; the structural adequacy of the bar in any member; the permitted tolerance on the actual product; 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. It is not acceptance evidence, it is not a weighbridge result, and it does not verify what physically arrived.
Practical consequence: take the cut list from a fixed schedule revision, name the document that supplies the bends, compute on a basis you can reproduce, and keep the weighed mass and its tolerance as a separate commercial record.
FAQ
What an estimator asks about 8 mm bar before ordering
Written for the takeoff and detailing decisions that have to be right before a cut-and-bent order can be placed.
How much does 8 mm rebar weigh per metre?
A nominal 8 mm round bar has a nominal cross-sectional area of about 50.3 mm², and at the standard steel density convention of 7,850 kg/m³ that gives a nominal mass of approximately 0.395 kg/m. The important part is the word nominal, and the fact that the basis is stated: that figure is geometry multiplied by a density, not a measured weight. The commercial mass of a shipment is established separately, and the permitted tolerance on the actual bar is read from the printed standard your order names. This page always prints the formula alongside the figure so it can be checked rather than taken on trust.
Why is 8 mm usually ordered as stirrups and links rather than as main bars?
Because that is the role the diameter is detailed into. At 8 mm the bar is small enough to be bent repeatedly to tight, repetitive shapes, which is what a stirrup or a link is, and it is what distribution steel in a slab does. It is rarely the bar carrying the primary load. The practical consequence for a buyer is that the order is a large count of short, identical, fabricated pieces rather than a modest count of long straight ones — so the risk concentrates in the bend detail and the cut length, and an error in either is repeated thousands of times.
Can this page give me the lap length or bend diameter for 8 mm bar?
No, and it is not a gap in the page — those values are not derivable from a diameter alone. Lap and anchorage lengths depend on the grade, the concrete strength, the cover, the bar's position in the member and the detailing provisions of the code your project adopted. Bend diameters and mandrel sizes depend on the governing standard and the bar's delivery condition. The takeoff checker on this page returns a mass estimate and deliberately returns no lap, bend, mandrel or hook value. Those come from the printed standard and your project's own detailing.
What does the takeoff checker on this page actually calculate?
It multiplies the nominal cross-sectional area derived from the nominal diameter, the cut length you enter, and the piece count you enter, at a stated density of 7,850 kg/m³. Every result prints that formula, the density and the nominal area it used, so you can reproduce it on a calculator and so anyone reviewing your enquiry can audit it. It is a theoretical nominal mass for estimating. It is not a weighbridge figure, it is not acceptance evidence, and it does not account for the tolerance band on the actual bar.
The cutter can only give me a guess at lengths — is it worth estimating anyway?
Yes, provided the guess is labelled as one. The checker treats a drawing take-off and a supplier's cut-and-bend proposal as distinct sources from an approved schedule revision, and it flags a result built on either so the basis is visible rather than buried. An early estimate on a stated basis is genuinely useful for budgeting and for comparing suppliers. What the flag is telling you is that the number should not yet become a purchase order until the schedule revision and the bend basis are fixed.
What evidence should arrive with a small-diameter consignment?
At minimum, evidence that identifies the consignment and the requirement it is being declared against — a mill test certificate for the heat, and the conformity document for the delivered lot in the terms the standard your order names requires. Where the bar is bought cut and bent, some of the evidence is produced at the fabricator rather than at the mill, so the two records have to reference the same consignment. And the dimensional check is your project's own receiving step: a nominal-diameter calculation is not a substitute for verifying what actually arrived.
Qualified RFQ
Request a quote for 8 mm Rebar
Copy the takeoff summary you have built, then send it to the commercial department. The enquiry is ready for review once the piece count, the cut length, the document supplying the bends and the destination are complete.
Price, stock, origin and lead time remain quotation-dependent unless current verified evidence is present. The mass estimate 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
Monday – Saturday: 8.00 AM – 6.00 PM · Sunday: Closed
Copyable takeoff summary
- Pieces
- To be confirmed
- Cut length
- To be confirmed
- Length source
- Not stated
- Bend basis
- Not stated
- Standard
- Not stated
- Edition
- Not stated
- Destination
- To be confirmed
Add any remaining open items — the schedule revision, the weighing basis, the required documents, availability, price or lead time — as explicit fields before sending.