Steel Bar Weight Calculator
Weight of steel bars (sariya / rebar) by diameter, length and number of bars.
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About the Steel Bar Weight Calculator
Steel is sold by weight, but drawings list bars by size and length. Choose the bar size (6 mm to 32 mm, or any custom diameter), the length of one bar and the number of bars to get the weight in kg and tonnes. Add the price per kg for a cost estimate.
Bar sizes are also shown in the common “sutar” numbering (#3 = 10 mm, #4 = 12 mm, #5 = 16 mm…).
How to use the Steel Bar Weight Calculator
- Choose the bar size.
- Choose feet or metres and enter the length of one bar (40 ft is common).
- Enter the number of bars and, optionally, the price per kg.
- Click Calculate weight.
Formula
Weight per metre (kg) = D² ÷ 162.2, where D is the diameter in mm. This comes from the density of steel, 7,850 kg/m³: π/4 × D² × 7,850 ÷ 1,000,000.
Total weight = weight per metre × length in metres × number of bars.
Examples
- One 12 mm bar, 40 ft long → 10.82 kg (0.888 kg per metre).
- 50 bars of 16 mm × 40 ft → 962.13 kg, almost a tonne.
Frequently asked questions
Why does the weight on the bill differ slightly?
Mills roll bars within allowed tolerances, so actual weight can be a few percent above or below the theoretical value.
How many 12 mm bars make a tonne?
About 92 bars of 40 ft (1,000 ÷ 10.82).