Steel rebar weight calculator
Calculate the weight of steel rebar from the diameter, length and quantity.
Based on standard steel: weight per meter = diameter² ÷ 162.2 (diameter in mm). Rebar usually comes in 12 m bars.
How the calculation works
A rebar's weight per meter comes from steel density (7850 kg/m³) applied to the cross-section: in practice, kg/m = diameter² ÷ 162.2 (diameter in mm). Multiply by length and number of bars for the total — handy for buying by weight.
Examples
- 8 mm rebar: 8² ÷ 162.2 ≈ 0.395 kg/m.
- 20 bars of 12.5 mm at 12 m each: ~231 kg total.
Frequently asked questions
How much does a 10 mm rebar weigh?
About 0.617 kg per meter. A 12 m bar weighs ~7.4 kg.
Where does 162.2 come from?
A constant folding in steel density (7850 kg/m³) and the circle area, giving kg/m from the diameter alone.
Why buy by weight not by bar?
Steel is sold by the kilo. The total weight helps budget and check the invoice.
How much does a rebar length weigh?
It depends on the gauge — a 12 m bar weighs about 2.94 kg at 6.3 mm and 11.56 kg at 12.5 mm.
Why is rebar sold by weight?
Because price follows material quantity. Weigh a sample on delivery — underweight bars mean out-of-spec gauge.
Are CA-50 and CA-60 interchangeable?
No. The number indicates yield strength, and substituting changes how the element behaves under load.
Does this define the reinforcement?
No. It converts length to weight for budgeting; the structural design must come from a qualified engineer.
Related calculators
Concrete volume
Work out how many cubic meters of concrete your slab or footing needs. Example: a 5 × 4 m slab 10 cm thick takes 2 m³.
Square footage
Enter width and length to get the area in square feet and square meters, adding several rooms at once. Example: a 10 × 12 ft bedroom is 120 sq ft.
Weight & mass converter
Convert kilograms, grams, milligrams, tons, pounds, ounces and arrobas.
More Construction calculators
See all →Wall paint
Calculate how many liters of paint and cans you need from area and number of coats.
Floor & tiles
Find out how many boxes of flooring or tile to buy for a room, including waste margin.
Bricks per wall
Calculate how many bricks or blocks you need from the wall area and brick size, including waste.
Stairs
Calculate the number of steps, riser height and tread depth from total height, using the Blondel rule.
Ramp slope
Calculate a ramp's slope in percentage, angle and ratio — and see if it is accessible.
Updated on June 30, 2026 · by Rafael Rossi · Methodology & sources