Rebar Calculator
Rebar weight, length and bars-per-tonne takeoff for any size list — free.
Enter each rebar size with length and quantity. The calculator computes weight per bar (π/4 × d² × 7850 kg/m³), total tonnes for your order and how many bars make one tonne — for both metric and US imperial sizes.
Rebar list
| # | Bar size | Bar length (m) | Qty |
|---|---|---|---|
| 1 |
Stirrups / ties
FAQ
How is rebar weight calculated?
Weight per metre follows the section formula π/4 × d² × 7850 kg/m³, which is the exact form of the classic d²/162 rule of thumb. Results match steel supplier tables within rounding.
Does it include laps and wastage?
No — enter the cut lengths you need. For laps, add the lap length to each bar; for wastage, add a percentage to the quantity (e.g. 3 extra bars per 100).
Can I use US bar sizes?
Yes, the size dropdown includes #3–#11 US bars alongside metric 6–40 mm. US sizes are converted to their metric diameters internally.