Calculate reinforcing bar weight from US #bar sizes or metric diameters, with worked examples and a practical bar-weight reference.
Fill in the first rebar row; use Add Row to enter additional diameters or bar lengths.
A rebar takeoff starts with the unit weight of each bar size, but a practical order also depends on total bar length, quantity, laps, hooks, anchorage and an appropriate waste allowance. CivilCalc lets you enter multiple bar groups so the net weight and planning total can be checked in one place.
Content and method reviewed: 19 September 2026
For metric bars, the common field approximation below follows from the circular steel area and a density near 7,850 kg/m³.
For US reinforcing bars, use the standard nominal lb/ft values shown below rather than converting a nominal #bar designation as though it were a diameter.
Use this table for quick quantity checks. US bar designations and metric diameters are shown as separate reference systems.
| US bar | Nominal lb/ft | Metric diameter | Approx. kg/m |
|---|---|---|---|
| #3 | 0.376 | 10 mm | 0.617 |
| #4 | 0.668 | 12 mm | 0.889 |
| #5 | 1.043 | 16 mm | 1.580 |
| #6 | 1.502 | 20 mm | 2.469 |
| #7 | 2.044 | 22 mm | 2.988 |
| #8 | 2.670 | 25 mm | 3.858 |
| #9 | 3.400 | 28 mm | 4.840 |
| #10 | 4.303 | 32 mm | 6.321 |
| #11 | 5.313 | — | — |
US and metric sizes are not exact one-to-one equivalents; the columns are convenient neighboring references, not substitution guidance.
| Bar group | Total length | Unit weight | Net weight |
|---|---|---|---|
| #3 ties | 1,400 ft | 0.376 lb/ft | 526 lb |
| #4 bars | 2,000 ft | 0.668 lb/ft | 1,336 lb |
| #5 bars | 1,700 ft | 1.043 lb/ft | 1,773 lb |
| #6 bars | 800 ft | 1.502 lb/ft | 1,202 lb |
| Total | 5,900 ft | — | ≈ 4,837 lb |
Steel weight per length follows cross-sectional area, so it grows approximately with the square of diameter. A modest increase in diameter can therefore produce a much larger increase in weight per foot or metre.
| US example | lb/ft | Relative to #4 |
|---|---|---|
| #4 | 0.668 | 1.00× |
| #5 | 1.043 | 1.56× |
| #6 | 1.502 | 2.25× |
| #8 | 2.670 | 4.00× |
| #10 | 4.303 | 6.44× |
The standard nominal weight of #5 rebar is about 1.043 lb/ft.
Using d²/162, 16 mm rebar is approximately 1.58 kg/m.
Keep the net drawing quantity separate from the purchasing quantity. Cutting, laps, detailing and site conditions should be reviewed before selecting a planning allowance.
Only the bar lengths entered in the calculator are counted. If laps, hooks or anchorage are not included in those lengths, add them separately from the project detailing.