Rebar Weight Calculator
Calculate rebar weight from ASTM A615 bar sizes. Add bars by size, length, and quantity to get the total weight in pounds and tons, plus a per-bar breakdown and optional cost. Free, no sign-up.
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Explanation
Rebar weight is what you order, price, and ship reinforcing steel by. In the United States, deformed reinforcing bars follow ASTM A615, which fixes a nominal diameter, cross-sectional area, and weight per foot for every bar size from #3 to #18. This calculator multiplies those nominal weights by your bar lengths and quantities to give a total weight in pounds and tons, a per-bar breakdown, and an optional material cost.
How rebar weight is calculated
Each bar size has a defined weight per linear foot. The weight of a take-off is simply the sum of every bar line, where each line is its weight per foot times the bar length times how many bars there are:
| Symbol | Meaning | Unit |
|---|---|---|
| W | Total rebar weight | lb |
| wsize | ASTM A615 nominal weight for that bar size | lb/ft |
| L | Length of one bar | ft |
| n | Number of bars of that size and length | — |
The bar number is the diameter in eighths of an inch: a #4 bar is 4⁄8 = ½ inch, a #8 bar is 8⁄8 = 1 inch. Above #11 the system jumps to #14 and #18, whose diameters no longer follow the eighths rule. Tons in this calculator use the 2,000 lb US short ton.
ASTM A615 rebar weight chart (#3–#18)
These nominal values are defined by ASTM A615 and do not change with grade — a #5 bar weighs 1.043 lb/ft whether it is Grade 60, Grade 75, or Grade 80. The soft-metric (A615M) designation is shown for reference; it labels the same bar by its rounded diameter in millimeters.
| Bar size | Metric (A615M) | Diameter (in) | Area (in²) | Weight (lb/ft) |
|---|---|---|---|---|
| #3 | #10M | 0.375 | 0.11 | 0.376 |
| #4 | #13M | 0.500 | 0.20 | 0.668 |
| #5 | #16M | 0.625 | 0.31 | 1.043 |
| #6 | #19M | 0.750 | 0.44 | 1.502 |
| #7 | #22M | 0.875 | 0.60 | 2.044 |
| #8 | #25M | 1.000 | 0.79 | 2.670 |
| #9 | #29M | 1.128 | 1.00 | 3.400 |
| #10 | #32M | 1.270 | 1.27 | 4.303 |
| #11 | #36M | 1.410 | 1.56 | 5.313 |
| #14 | #43M | 1.693 | 2.25 | 7.650 |
| #18 | #57M | 2.257 | 4.00 | 13.600 |
Source: ASTM A615/A615M, nominal dimensions and weights for deformed reinforcing bars. Areas and weights are nominal and assume a steel density of 0.2836 lb/in³.
Estimating notes and limitations
Standard mill lengths for straight bar are 20, 40, and 60 ft, though fabricated bars are cut and bent to the schedule. This calculator reports the theoretical weight of the bar lengths you enter. It does not add an allowance for laps and splices, hooks and bends, tie wire, chairs, or cutting waste, and it does not deduct for bend deductions — add your own percentage for those. The nominal weight already accounts for the deformations (ribs), so no extra factor is needed for deformed bar. Always confirm quantities against the structural drawings and the bar bending schedule.