How to use it
- Enter the Bar Diameter in millimetres, for example 12, 16 or 20.
- Enter the Length per Bar in metres. Stock bars are commonly 12 m; add lap length here if your schedule needs laps.
- Enter the Quantity of bars.
- Set Wastage (%) for cutting off-cuts and bending losses. The default is 3%.
- Read Weight per Meter (kg/m) and Total Weight (kg, with wastage). Divide by 1,000 for tonnes.
The formula
Weight per metre (kg/m) = D² ÷ 162, with D the bar diameter in millimetres. Total weight = weight per metre × length per bar × number of bars × (1 + wastage ÷ 100). The 162 comes from the density of steel (about 7,850 kg/m³) and the circular cross-section of the bar.
What changes the result
Weight grows with the square of the diameter: a 20 mm bar weighs about 2.8 times a 12 mm bar of the same length. Laps, hooks and bends add length that is not in the drawing length, so add them to the Length per Bar or to the wastage. The result is a theoretical weight; mill tolerance means the delivered weight can differ slightly.
Ordering and handling on UAE sites
Rebar is bought by the tonne, and bundles of 12 m bars are heavy and long, so plan the unloading and placing before delivery. A mobile crane, truck crane or telehandler is usually used for bundles, and long bars need a flatbed or trailer. Check the grade and the supplier test certificates that the specification calls for.
Worked examples
- Twenty 16 mm bars, 12 m long, weigh 390.637 kg including 3% wastage; a 16 mm bar weighs 1.58 kg/m.
- A hundred 12 mm bars of 12 m come to 1,098.667 kg with 3% wastage - the load a flatbed and a crane need to be planned for.
- Forty 25 mm bars for a heavy beam or pile cap: 3.858 kg/m each metre, 1,907.407 kg in total.
Rebar weight by diameter
Printable chart| Bar diameter (mm) | Weight per metre (kg/m) | 12 m bar (kg) |
|---|---|---|
| 6 | 0.222 kg/m | 2.667 kg |
| 8 | 0.395 kg/m | 4.741 kg |
| 10 | 0.617 kg/m | 7.407 kg |
| 12 | 0.889 kg/m | 10.667 kg |
| 14 | 1.21 kg/m | 14.519 kg |
| 16 | 1.58 kg/m | 18.963 kg |
| 18 | 2 kg/m | 24 kg |
| 20 | 2.469 kg/m | 29.63 kg |
| 22 | 2.988 kg/m | 35.852 kg |
| 25 | 3.858 kg/m | 46.296 kg |
| 28 | 4.84 kg/m | 58.074 kg |
| 32 | 6.321 kg/m | 75.852 kg |
| 36 | 8 kg/m | 96 kg |
| 40 | 9.877 kg/m | 118.519 kg |
Theoretical weight with no wastage, using D² ÷ 162. The last column is one 12 m stock bar.
Frequently asked questions
What is the formula for rebar weight?
Weight in kg per metre is the diameter in millimetres squared, divided by 162. Multiply by the length and the number of bars for the total.
How much does a 12 mm bar weigh per metre?
Use D² ÷ 162 with D = 12, as in the table above. A 12 m bar weighs twelve times the per-metre value.
How do I convert rebar weight to tonnes?
Divide the total weight in kilograms by 1,000. Suppliers quote and invoice steel by the tonne.
Does the calculator include laps?
Not on its own. Add the lap length to the Length per Bar, or raise the wastage percentage.
How much wastage should I allow on rebar?
About 3% is a common allowance for cutting off-cuts; complex bending can need more. Your steel fixer or QS can tell you what the schedule needs.
Equipment for this job
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<iframe src="https://www.equipmentsfinder.com/embed/field-tools/steel-rebar-weight-calculator" title="Steel rebar weight calculator" width="100%" height="620" style="border:0;max-width:720px" loading="lazy"></iframe> <p style="font-size:12px"><a href="https://www.equipmentsfinder.com/en-us/field-tools/steel-rebar-weight-calculator">Steel rebar weight calculator</a> by <a href="https://www.equipmentsfinder.com">EquipmentsFinder</a></p>