Rebar Weight Calculator
Pick a bar diameter, enter length and quantity to get weight per metre, per bar and total tonnage.
With the default inputs: Bar diameter Φ12 · Length per bar 9 · Quantity 100 pcs etc.Total weight 0.824 t
Edit the inputs below to recalculate.Inputs
Result
| Weight per metre | 0.8885kg/m |
| Weight per bar | 7.996kg |
| Total length | 900.0m |
| Net weight | 799.6kg |
| With waste | 823.6kg |
| Tonnage | 0.824t |
Weights use the 0.00617d² formula; permitted deviations are set out in GB/T 1499.2.
Reverse: known result, work out one input
Enter a target result; the other inputs stay fixed and this one is worked out.
Formula
| Weight per metre | w = 0.00617 × d² (kg/m, d in mm) |
| Per bar | W = w × L |
| Total | W_total = w × L × N × (1 + waste %) |
Standard rebar weight per metre (GB/T 1499.2)
| Size | kg per m | 9 m bar (kg) | 12 m bar (kg) |
|---|---|---|---|
| Φ6 | 0.222 | 2.00 | 2.66 |
| Φ8 | 0.395 | 3.56 | 4.74 |
| Φ10 | 0.617 | 5.55 | 7.40 |
| Φ12 | 0.888 | 7.99 | 10.66 |
| Φ14 | 1.21 | 10.89 | 14.52 |
| Φ16 | 1.58 | 14.22 | 18.96 |
| Φ18 | 2.00 | 18.00 | 24.00 |
| Φ20 | 2.47 | 22.23 | 29.64 |
| Φ22 | 2.98 | 26.82 | 35.76 |
| Φ25 | 3.85 | 34.65 | 46.20 |
| Φ28 | 4.83 | 43.47 | 57.96 |
| Φ32 | 6.31 | 56.79 | 75.72 |
How to work it out
- Confirm diameter and grade: 12 mm HRB400 and HPB300 weigh the same, but stock lengths and bend allowances differ.
- Use d²/162 or 0.00617 × d² for weight per metre — 0.888 kg/m at 12 mm, 3.85 kg/m at 25 mm.
- Multiply by total length; where stock lengths of 9 m or 12 m apply, counting bars is more accurate.
- Measure stirrups on the centreline, not the outside — the two differ by 3-5%.
- Total by size: quote on theoretical weight, purchase on weighed weight plus a 2-4% margin.
Where it goes wrong
- Treating 6.5 mm as 6 mm — 0.038 kg per metre, which is 1.7 tonnes of discrepancy on a ten-tonne order.
- Taking stirrup weight from (beam width + depth) × 2 — hooks are missed and bend deductions are overstated; the result leans high but is not accurate.
- Using theoretical weight for both settlement and purchasing — a positive-tolerance batch then leaves you short.
Material and cost
Deformed bar HRB400 sits around 3800-4300 per tonne in 2026 with wide regional and size variation; below 12 mm and above 32 mm usually carry a 50-150 per tonne premium. Settlement is theoretical weight against the contract rate and the supplier carries the weighbridge difference — so the purchase contract must state which basis applies.
On site
- On delivery, measure three bars for actual length and diameter, weigh a bundle and back-calculate whether the deviation is within ±4%.
- Store different grades of the same diameter separately with tags; mixing them is a common cause of structural incidents.
- Optimise cutting before you cut: a 9 m bar cut at 2.9 m leaves 0.3 m of scrap, while 3.0 m is exact.
Basis
- GB/T 1499.2-2018 Steel for reinforced concrete — hot-rolled ribbed bars (nominal area and mass)
- GB 50010-2010 (2015 edition) Code for design of concrete structures, Section 4.2
- GB 50204-2015 Code for acceptance of concrete structures, Chapter 5 (reinforcement)
FAQ
Where does the 0.00617 factor come from?
Should lap and anchorage lengths be included?
Why does the scale weight differ from the theoretical weight?
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Rebar Weight Calculator. 2026-10-25. https://jianzhujisuan.com/en/rebar-weight