Rebar and steel weight calculator
Weight of reinforcement bars by diameter, length and number.
How it is calculated
Weight per metre = π ÷ 4 × d² × 7,850 kg/m³ = d² ÷ 162.2 (d in mm), often rounded to d² ÷ 162. Total = weight per metre × length × number of bars.
How to use the Steel Weight Calculator
Work out the weight of steel reinforcement bars (rebar) from the bar diameter, length and number, for estimates, bar bending schedules and orders.
- Choose the bar diameter in millimetres, or the US bar number in imperial mode.
- Enter the length of one bar and the number of bars.
- Read the weight per metre, the weight of one bar and the total weight in kilograms and tonnes.
- Use the bar table to compare standard diameters.
Worked example
A 12 mm bar weighs 0.888 kg per metre (the D²/162 rule gives 0.889). Ten 12 m bars are 120 m of steel and weigh about 106.5 kg, or 0.107 tonnes.
Good to know
- The weight is the bar's cross-section area × steel density (7,850 kg/m³). D²/162 is the same formula as a quick rule for kg per metre with D in millimetres.
- Add laps, hooks and bends to the bar length from your bar bending schedule before totalling.
- Mills supply bars in standard lengths, often 12 m, so round orders to whole bars.
Questions
Where does D²/162 come from?
Steel weighs 7,850 kg/m³. A bar of diameter d mm weighs π/4 × d² × 7,850 ÷ 1,000,000 kg per metre, which is d² ÷ 162.2.
Is anything I enter saved or sent?
No. The calculation runs in your browser. Nothing you type is sent anywhere. You can copy the result, print it or download it as a CSV.