Welding and Metalwork Calculators
Rebar weight calculator.
Choose a US bar size (#3 to #18) or a metric bar (10M to 55M), then enter the length and number of bars for the weight in pounds, kilograms and tonnes. Runs in your browser; nothing is sent or stored.
Inputs
Result
Fill the form and press Calculate.
Answer first. A #4 rebar (1/2 in) weighs 0.668 lb per foot, which is 0.994 kg per metre, so a 20 ft bar weighs 13.36 lb (6.06 kg). A 15M metric bar weighs 1.570 kg per metre.
Worked example
One hundred #8 bars cut to 6 m: #8 is 2.670 lb/ft = 3.973 kg/m, so one bar is 23.84 kg and the order is 2,384 kg (2.38 tonnes, about 5,256 lb).
How it works
Weights used. The tool multiplies the published linear weight by the total length. Inch-pound bars use the Gerdau table for ASTM A615 / A706 bars (#3 0.376, #4 0.668, #5 1.043, #6 1.502, #7 2.044, #8 2.670, #9 3.400, #10 4.303, #11 5.313, #14 7.650, #18 13.600 lb/ft). Metric bars use the same table's kg/m figures for the CSA G30.18 sizes. Conversions use 1 lb = 0.45359237 kg and 1 ft = 0.3048 m.
Bar numbers. For #3 to #8 the bar number is the nominal diameter in eighths of an inch (#4 is 4/8 = 1/2 in). The number in brackets after a US size is its soft-metric designation in millimetres, for example #4 (13). That is not the same bar as a Canadian 10M or 15M: 10M is 100 mm2 and 0.785 kg/m, heavier than a #3 at about 0.56 kg/m.
Nominal weight. These are nominal weights. Delivered bars vary within the mill tolerance, and tie wire, laps and cut waste are not included, so check the delivery ticket and allow for lap length when you order.
Rebar weight charts
| US bar | Metric designation (mm) | lb per ft | kg per m |
|---|---|---|---|
| #3 | 10 | 0.376 | 0.560 |
| #4 | 13 | 0.668 | 0.994 |
| #5 | 16 | 1.043 | 1.552 |
| #6 | 19 | 1.502 | 2.235 |
| #7 | 22 | 2.044 | 3.042 |
| #8 | 25 | 2.670 | 3.973 |
| #9 | 29 | 3.400 | 5.060 |
| #10 | 32 | 4.303 | 6.404 |
| #11 | 36 | 5.313 | 7.907 |
| #14 | 43 | 7.650 | 11.384 |
| #18 | 57 | 13.600 | 20.239 |
| Metric bar | kg per m | lb per ft |
|---|---|---|
| 10M | 0.785 | 0.527 |
| 15M | 1.570 | 1.055 |
| 20M | 2.355 | 1.582 |
| 25M | 3.925 | 2.637 |
| 30M | 5.495 | 3.692 |
| 35M | 7.850 | 5.275 |
| 45M | 11.775 | 7.912 |
| 55M | 19.625 | 13.187 |
Sources
- Straight Rebar, size and linear weight tables (Gerdau) (opened 2026-10-15)
- Rebar, nominal diameters of US bar sizes (Wikipedia) (opened 2026-10-15)
Gerdau lists the weights for ASTM A615 (grades 40, 60, 75, 80, 100), ASTM A706 (grades 60, 80) and CSA G30.18-21 bars. The Wikipedia article is used only for the nominal diameters.
FAQ
How much does a #4 rebar weigh?
0.668 lb per foot (0.994 kg per metre). A 20 ft stick weighs 13.36 lb (6.06 kg).
How much does a #3 rebar weigh?
0.376 lb per foot, about 0.560 kg per metre.
How much does 10M rebar weigh per metre?
0.785 kg per metre, from the Gerdau metric table. 15M is 1.570 kg/m and 20M is 2.355 kg/m.
Is #3 rebar the same as 10M?
No. #3 is about 0.560 kg/m and 10M is 0.785 kg/m, so a 10M bar is heavier.
Does this include laps and waste?
No. It is the weight of the bar lengths you enter. Add lap splices, hooks and cut waste to the length first.