Rebar weight calculator
Calculate total weight of steel rebar from bar diameter, length and count. Uses the standard formula: unit weight = 0.006165 × d² kg/m.
Inputs
Results
Total weight
Enter your measurements to see the result
kilograms (kg)
Unit weight
—
kg/m
Tonnes
—
ton
Total length
—
m (incl. splice)
Weight per bar
—
kg/bar (no splice allowance)
⚠ Formula: W = 0.006165 × d²(mm) kg/m (steel at 7,850 kg/m³). Results are nominal weights; bar standards allow actual mass to differ within set tolerances, so use the supplier's weights for ordering or payment.
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Frequently asked questions
How do I calculate rebar weight?
Use the formula: unit weight (kg/m) = 0.006165 × diameter² (in mm). Multiply this by the total length of rebar to get the total weight in kilograms.
What is a lap splice and how much extra rebar do I need?
A lap splice is the overlap where two bars are joined. Lap length is set by the design — for IRC footings and concrete walls it comes from Table R608.5.4(1) — so there is no fixed percentage. Work out the allowance as total lap length ÷ total bar run; for example, one 0.6 m lap for every 6 m of run adds 10%. The IRC also asks for bars in the longest lengths practical to keep splices to a minimum.
How much does a 12mm rebar weigh per meter?
A 12mm rebar weighs approximately 0.888 kg per meter, calculated as 0.006165 × 12² = 0.8878 kg/m.
How do I convert rebar weight to tonnes?
Divide the total weight in kilograms by 1000 to get tonnes. For example, 1,500 kg of rebar equals 1.5 tonnes.