Rebar weight table
Every bar size from 6 mm to 40 mm: kg per metre, weight per 9 m and 12 m bar, metres per tonne.
| Bar | Weight (kg/m) | 9 m bar (kg) | 12 m bar (kg) | Metres per tonne |
|---|---|---|---|---|
| Φ6 | 0.222 | 2.00 | 2.66 | 4505 |
| Φ6.5 | 0.260 | 2.34 | 3.12 | 3846 |
| Φ8 | 0.395 | 3.56 | 4.74 | 2532 |
| Φ10 | 0.617 | 5.55 | 7.40 | 1621 |
| Φ12 | 0.888 | 7.99 | 10.66 | 1126 |
| Φ14 | 1.21 | 10.89 | 14.52 | 826 |
| Φ16 | 1.58 | 14.22 | 18.96 | 633 |
| Φ18 | 2.00 | 18.00 | 24.00 | 500 |
| Φ20 | 2.47 | 22.23 | 29.64 | 405 |
| Φ22 | 2.98 | 26.82 | 35.76 | 336 |
| Φ25 | 3.85 | 34.65 | 46.20 | 260 |
| Φ28 | 4.83 | 43.47 | 57.96 | 207 |
| Φ32 | 6.31 | 56.79 | 75.72 | 158 |
| Φ36 | 7.99 | 71.91 | 95.88 | 125 |
| Φ40 | 9.87 | 88.83 | 118.44 | 101 |
All values are computed from the stated formulas; ranges show the usual spread. Use measured data or the local code where it differs.
How to use this table
- For bills of quantities and settlement, multiply theoretical weight by total length and skip the weighbridge.
- For purchasing, accept by actual weight — hot-rolled deformed bar often rolls to positive tolerance and runs 2-4% heavy.
- For lifting and haulage, work out the bundle weight first, then check the crane chart at that radius.
- Lifting weight: total cage mass = total length per diameter × theoretical mass, then ×1.1 for the lifting gear before checking the crane's rated capacity.
- Reconciliation: the engineer checks against theoretical mass, so 3-5% under the weighbridge figure is normal negative-tolerance supply and is not a claimable loss.
- Cutting plans: work out utilisation against 9 m or 12 m stock first; below about 92%, mechanical couplers usually beat short offcuts.
Common misuse
- Treating 6.5 mm as 6 mm — 0.038 kg per metre, which is real money over a tonne.
- Taking stirrup weight from the outside dimensions — measure the centreline and deduct bend allowances, or you overclaim 3-5%.
- Confusing plain round bar with deformed bar — identical weight for the same diameter, but different stock lengths and bend allowances.
- Reading Φ as an internal diameter. Φ12 is the nominal diameter, neither bore nor outside diameter, and ribbed bars are weighed on nominal diameter — the ribs' extra volume is ignored.
- Adding a factor because ribbed bars 'should be heavier'. HRB400 and HPB300 of the same diameter weigh exactly the same; what differs is strength, not mass.
Calculate the actual number
Rebar Weight CalculatorPick a bar diameter, enter length and quantity to get weight per metre, per bar and total tonnage.Rebar Cut Length CalculatorCut length and bar weight with standard hook allowances.Rebar Mesh Weight CalculatorWeight per square metre and total mesh weight from dimensions and spacings.
Other reference tables
FAQ
How do I calculate rebar weight per metre?
0.00617 × diameter², i.e. d²/162. That is 0.888 kg/m for 12 mm and 3.85 kg/m for 25 mm.
How many metres of 12 mm bar in a tonne?
1000 ÷ 0.888 ≈ 1126 m, or 125 lengths of 9 m and 94 lengths of 12 m.
Why does theoretical weight differ from the weighbridge?
Theoretical weight uses 7850 kg/m³ and nominal dimensions; ribs, rolling tolerance and corrosion shift the real figure by 1-4%.
How far can actual mass deviate from theoretical?
GB/T 1499.2 permits ±7% for Φ6-Φ12, ±5% for Φ14-Φ20 and ±4% for Φ22-Φ50. A delivery 4-7% light is therefore compliant, and a claim on that difference will not stand.
How is strand mass per metre calculated?
From nominal area for 1×7 standard strand: Φ15.2 is 140 mm² at 1.101 kg/m, Φ12.7 is 98.7 mm² at 0.775 kg/m and Φ17.8 is 191 mm² at 1.50 kg/m. Do not use d²/162 — that formula only applies to hot-rolled bar.
How is the percentage of lapped bars calculated?
Within one connecting zone (1.3 times the lap length), lapped bar area ÷ total bar area. In tension zones of beams and slabs it should not exceed 25%, and 50% in compression; beyond that the code applies a lap length multiplier.
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.