The D²L/162 formula
For a round bar, theoretical Weight (kg) = D² × L ÷ 162, where D is diameter in millimetres and L is length in metres.
Worked example
A 12 mm bar of 10 m length weighs approximately 12² × 10 ÷ 162 = 8.89 kg theoretically.
How to use the calculator
Enter nominal diameter and bar length. The result is a theoretical weight. For detailed reinforcement, use the lengths from an approved BBS.
Where it is used
The method is useful for preliminary steel estimates, procurement checks, stock reconciliation and learning.
Limitations
Actual quantities can include laps, hooks, bends, couplers and cutting waste. These must be handled in detailed reinforcement calculations.
Use the Rebar Weight Calculator
Enter your project values and get a quick preliminary calculation.
Engineering note: Results are intended for preliminary estimation, planning and learning. Verify measurements, drawings, specifications, current rates, applicable standards and site conditions before construction or safety-critical decisions.
Frequently Asked Questions
What is the steel weight formula?
D² × L ÷ 162 is a common theoretical formula for round reinforcement.
What is the weight of 12 mm steel per metre?
Approximately 0.889 kg per metre theoretically.
Does it include lap length?
Only the length entered is included.
Can it replace a BBS?
No. A BBS is better for detailed reinforcement quantity.