Rebar Weight Calculator
Estimate nominal reinforcing-bar mass from diameter, length and count using an approximate diameter-squared rule for steel bars.
How to use this calculator
- Enter nominal diameter in millimetres, length per bar in metres and an integer quantity.
- Review the worked example for rebar weight calculator and compare the inputs with your own units.
- Change one assumption at a time and recalculate if you need a second scenario.
Approximate steel mass
Approximate kg per metre = diameter² ÷ 162; total mass = kg per metre × length × quantity.
- The rule uses nominal bar diameter in millimetres and produces an approximate standard mass for planning quantities.
- The result is calculated from the values entered; the page does not independently verify assumptions, data quality or real-world suitability.
Worked examples
Ten 12 mm bars
A 12 mm bar is estimated near 12²/162 = 0.889 kg/m. Ten bars each 12 m long total about 106.7 kg.
144 ÷ 162 ≈ 0.889 kg/m; 0.889 × 12 × 10 ≈ 106.7 kg.
Estimated total mass is approximately 106.7 kg.
Understanding the result
Count and length scale total mass linearly under the same nominal diameter assumption.
Bar standards, nominal diameters, actual supply, laps, cutting waste and project engineering requirements may change the order quantity.
Important notes
Use the relevant supplied bar standard and structural drawings for procurement.
Displayed figures are rounded for readability. Preserve more precision during intermediate calculations and verify the labels and units before using the estimate.
Frequently asked questions
What does the Rebar Weight Calculator show?
Count and length scale total mass linearly under the same nominal diameter assumption.
What assumptions should I check?
Use the relevant supplied bar standard and structural drawings for procurement.
Does this replace expert or authoritative guidance?
Bar standards, nominal diameters, actual supply, laps, cutting waste and project engineering requirements may change the order quantity.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.