Rebar Weight Calculator
Find the exact weight of any rebar size by length and quantity, using ASTM A615 standard values. Get total pounds, tons, linear feet and the number of 20-ft sticks to order.
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Rebar weight depends only on bar size, never on grade. A #4 bar weighs 0.668 lb per foot, a #5 weighs 1.043 lb/ft, and a #3 weighs 0.376 lb/ft — the three sizes that cover almost all residential work. Multiply weight-per-foot by your total linear feet to get the order weight. A Grade 40 and a Grade 60 bar of the same size weigh exactly the same; grade sets strength, not mass.
Rebar weight chart (ASTM A615)
Every US rebar size follows ASTM A615, which fixes the diameter, cross-sectional area and weight per foot. These figures are identical from any mill.
| Size | Diameter | Weight / ft | Weight / m | Area (in²) | 20-ft stick |
|---|---|---|---|---|---|
| #3 | 0.375″ (10 mm) | 0.376 lb | 0.560 kg | 0.11 | 7.5 lb |
| #4 | 0.500″ (13 mm) | 0.668 lb | 0.994 kg | 0.20 | 13.4 lb |
| #5 | 0.625″ (16 mm) | 1.043 lb | 1.552 kg | 0.31 | 20.9 lb |
| #6 | 0.750″ (19 mm) | 1.502 lb | 2.235 kg | 0.44 | 30.0 lb |
| #7 | 0.875″ (22 mm) | 2.044 lb | 3.042 kg | 0.60 | 40.9 lb |
| #8 | 1.000″ (25 mm) | 2.670 lb | 3.973 kg | 0.79 | 53.4 lb |
| #9 | 1.128″ (29 mm) | 3.400 lb | 5.060 kg | 1.00 | 68.0 lb |
| #10 | 1.270″ (32 mm) | 4.303 lb | 6.404 kg | 1.27 | 86.1 lb |
| #11 | 1.410″ (36 mm) | 5.313 lb | 7.907 kg | 1.56 | 106.3 lb |
| #14 | 1.693″ (43 mm) | 7.650 lb | 11.38 kg | 2.25 | 153.0 lb |
| #18 | 2.257″ (57 mm) | 13.600 lb | 20.24 kg | 4.00 | 272.0 lb |
How rebar weight is calculated
The tool uses the published ASTM weight per foot, but you can check any figure two ways.
And a field shortcut that gets you within 1%: the weight per foot is roughly the bar number squared, divided by 24. A #5 bar: 5² ÷ 24 = 1.04 lb/ft, against the listed 1.043. It works because reinforcing steel weighs about 490 lb per cubic foot, and the bar number is the diameter in eighths of an inch.
Why grade doesn’t change the weight
Rebar grade — 40, 60, 75, 80 — is the minimum yield strength in thousands of psi. It describes how much force the steel resists before it deforms, not how much steel is there. A Grade 40 #5 and a Grade 60 #5 are the same diameter and the same weight per foot; only their strength differs. So for ordering and freight, use the size-based chart above and ignore the grade entirely.
Don’t forget lap splices
Rebar ships in 20-ft and 40-ft sticks. Any run longer than a stick needs a lapped overlap where two bars run side by side to transfer the load — and that overlap is extra steel you have to buy. A tension lap is roughly 40 bar diameters, so a #4 lap is about 20 inches. On a typical slab, laps add 5–10% to the total linear feet. Size them with the rebar lap splice calculator, and work out how many bars a slab needs with the rebar spacing calculator.
Frequently asked questions
How much does a #4 rebar weigh per foot?
A #4 bar (½-inch diameter) weighs 0.668 lb per foot under ASTM A615. A standard 20-ft stick weighs 13.4 lb. It’s the most common size in residential slabs, driveways and footings.
How much does a stick of rebar weigh?
Standard sticks are 20 ft. A #3 stick is 7.5 lb, #4 is 13.4 lb, #5 is 20.9 lb, and #6 is 30.0 lb. Multiply weight-per-foot by 20 for any size.
Does rebar grade affect the weight?
No. Grade 40, 60, 75 and 80 differ in strength, not size. A Grade 40 #5 weighs the same as a Grade 60 #5 — 1.043 lb/ft. Weight is set by diameter alone.
How do I convert rebar weight to tons?
Divide total pounds by 2,000 for US (short) tons. 800 lb of rebar is 0.40 tons. Steel is ordered and freighted by weight, so this matters for delivery planning.
What does the bar number mean?
The number is the diameter in eighths of an inch. A #4 is 4/8″ = ½”. A #8 is 8/8″ = 1″. This holds cleanly from #3 through #8.