About this calculator
Choose mild steel, stainless steel, aluminium, copper, brass or another metal, or enter your own density. Add the rate per kg to estimate the cost.
How to use it
- Choose the metal and shape.
- Enter the dimensions in mm and the length.
- Enter the number of pieces and, if you like, the rate.
The formula
Weight = cross-section area × length × density
- Area
- round: πd² ÷ 4; pipe: π(D² − d²) ÷ 4; flat: width × thickness; angle: t × (a + b − t)
- Density
- mild steel 7,850 kg/m³; aluminium 2,700; copper 8,960
Worked example
Ten 12 mm TMT bars, each 12 m long
- Area = π × 12² ÷ 4 = 113.1 mm²; weight = 0.888 kg per metre.
- One bar = 10.65 kg; ten bars = 106.5 kg.
What the result means
For steel rounds the site shortcut is d² ÷ 162 kg per metre, which gives almost the same answer.
Assumptions
- Solid, uniform metal with sharp corners.
Limitations
- Rolled sections have rounded corners and a weight tolerance, so actual weight can differ by a few percent.
Frequently asked questions
What is the formula d² ÷ 162?
A shortcut for the weight per metre of a steel round bar, with d in mm. It comes from π ÷ 4 × 7,850 ÷ 10⁶.
What is the weight of a 12 mm rod?
0.888 kg per metre, or about 10.65 kg for a 12 m length.
How do I find the weight of an MS plate?
Length × width × thickness (in metres) × 7,850. A 1 m × 1 m × 1 mm sheet weighs 7.85 kg.
Last reviewed on 7 October 2026. Found a mistake? Tell us.