Case 1
- Bar designation
- Metric 12 mm
- Total length
- 100m
88.8kg
Open with these valuesRebar Weight Calculator
88.8kg
Result: 88.8 kgWeight comes from the nominal cross-section, so the bar designation is all you need beside the length. Watch the ASTM numbering: #3 to #8 are eighths of an inch, but #9 and up are tabulated diameters that no longer follow that rule.
The numbers at a glance
Held fixed: Bar designation Metric 12 mm.
| Total length (m) | Result (kg) |
|---|---|
| 25.00 | 22.2 |
| 50.00 | 44.4 |
| 75.00 | 66.6 |
| 100.00Your value | 88.8 |
| 125.00 | 111.0 |
| 150.00 | 133.2 |
| 175.00 | 155.4 |
| 200.00 | 177.6 |
Worked examples
Case 2
- Bar designation
- Metric 25 mm
- Total length
- 240m
924.8kg
Open with these valuesCase 3
- Bar designation
- #4 — 12.7 mm
- Total length
- 304.8m
303.1kg
Open with these valuesHow it's calculated
kg = π·(d/2)² · length · 7850 kg/m³
- StepPick the bar designation — EN sizes are the diameter in mm.
- StepSwitch the units above if you work in feet and pounds.
- StepEnter the total length of all bars added together.
- ResultRead the weight; laps and offcuts are not included.
Reference table
| Designation | Diameter | Weight per metre |
|---|---|---|
| m12 / #4 | 12 mm / 12.7 mm | 0.888 kg / 0.994 kg |
| m16 / #5 | 16 mm / 15.875 mm | 1.578 kg / 1.554 kg |
| m20 / #6 | 20 mm / 19.05 mm | 2.466 kg / 2.237 kg |
| m25 / #8 | 25 mm / 25.4 mm | 3.853 kg / 3.978 kg |
Questions
How much does rebar weigh per metre?
A 12 mm bar weighs 0.888 kg per metre, a 10 mm bar 0.617 and a 20 mm bar 2.466. Enter a total length of 1 to read the figure for any size.
Why does a 20 mm bar weigh four times a 10 mm bar?
Because the weight follows the cross-section, which grows with the square of the diameter. Doubling the diameter multiplies the area, and so the weight, by four — 0.617 against 2.466 kg per metre.
How much does US rebar weigh per foot?
A #4 bar weighs 0.668 lb per foot and a #8 bar 2.673 — the same factor of four, since a #8 is twice the diameter of a #4.
Is this the nominal weight?
Yes: the nominal diameter times the density of steel. A real bar is ribbed and varies within tolerance, so a delivery note can differ by a percent or two.
Do I enter the number of bars or the total length?
The total length. For 25 bars of four metres, enter 100.
Sources and last check
Information, not professional advice.