Steel Weight Calculator
Weight of TMT bars, rods, pipes, plates, angles and channels in kg, with cost
| Bar size | kg per metre | kg per 12 m bar | Bars per tonne |
|---|---|---|---|
| 8 mm | 0.395 | 4.74 | 211 |
| 10 mm | 0.617 | 7.4 | 135 |
| 12 mm | 0.888 | 10.65 | 94 |
| 16 mm | 1.578 | 18.94 | 53 |
| 20 mm | 2.466 | 29.59 | 34 |
| 25 mm | 3.853 | 46.24 | 22 |
| 32 mm | 6.313 | 75.76 | 13 |
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Results are for general guidance. Please check anything important before relying on it. Terms of use
How to Use
- Pick the shape: round bar or TMT rebar, square or flat bar, plate or sheet, round pipe, hollow section, equal angle or channel.
- Enter the dimensions in mm (diameter, width, thickness, wall and so on, depending on the shape).
- Choose metres or feet, enter the length of one piece and the number of pieces.
- Leave the density at 7,850 kg/m³ for mild and TMT steel, or change it for stainless steel or aluminium.
- Add your dealer's price per kg to see the cost. The weight per metre, per piece and in total update as you type, with a TMT bar weight chart below.
How steel weight is calculated
Steel is bought by weight but measured by size, so you need to turn one into the other: to check a dealer's bill, to estimate the cost of a gate or shed, or to work out how many TMT bars make a tonne. This steel weight calculator finds the area of the cross-section from your dimensions and multiplies it by the length and the density of steel.
Mild steel and TMT bars weigh about 7,850 kg per cubic metre. That's the figure used in Indian standards and site practice. Change it for other metals: stainless steel is about 8,000 and aluminium about 2,700.
The D²/162 rule for TMT bars
For a round bar, the area is π/4 × d². Put in the density and the units, and the weight per metre becomes:
12 mm bar: 12 × 12 ÷ 162.2 = 0.888 kg per metre
Site engineers often round it to d²/162. TMT bars in India are made to IS 1786 and usually sold in 12 m lengths. The standard allows a small tolerance on mass, so a bar from the mill can weigh slightly more or less than the chart.
| Bar size | kg per metre | kg per 12 m bar | Bars per tonne (about) |
|---|---|---|---|
| 8 mm | 0.395 | 4.74 | 211 |
| 10 mm | 0.617 | 7.40 | 135 |
| 12 mm | 0.888 | 10.65 | 94 |
| 16 mm | 1.578 | 18.94 | 53 |
| 20 mm | 2.466 | 29.59 | 34 |
| 25 mm | 3.853 | 46.24 | 22 |
| 32 mm | 6.313 | 75.76 | 13 |
Other shapes
- Flat bar or plate: width × thickness. A 50 × 6 mm flat weighs 300 × 7,850 ÷ 10,00,000 = 2.36 kg per metre.
- Round pipe: π/4 × (OD² − ID²), where ID = OD − 2 × wall. A 40 NB pipe (48.3 mm OD, 3.2 mm wall) works out to about 3.56 kg per metre.
- Square or rectangular hollow section: outer area minus inner area. Real tubes have rounded corners, so they are a little lighter.
- Angle and channel: treated as flat plates joined together. Rolled sections have rounded roots and channels have sloping flanges, so use the IS 808 tables or the mill's catalogue when you need exact figures.
Worked example
You need 40 bars of 12 mm and 25 bars of 8 mm for a slab. The 12 mm bars weigh 40 × 10.65 = 426 kg and the 8 mm bars 25 × 4.74 = 118.5 kg, so about 545 kg in all. At ₹60 a kg that is roughly ₹32,700 before GST and transport. Steel prices change every week, so use your dealer's current rate.
Tips
- Sheet gauges vary between makers. Measure the thickness with a vernier if the weight matters.
- When buying by weight, ask the dealer to weigh the bundle in front of you and compare it with this chart.
- Add a few percent for laps, hooks and offcuts when ordering rebar.