US Rebar Size Chart — Weight per Foot
| Bar size | Diameter (in) | Weight per foot (lb) | Weight per meter (kg) |
|---|---|---|---|
| #3 | 0.375” | 0.376 | 0.560 |
| #4 | 0.500” | 0.668 | 0.994 |
| #5 | 0.625” | 1.043 | 1.552 |
| #6 | 0.750” | 1.502 | 2.235 |
| #7 | 0.875” | 2.044 | 3.041 |
| #8 | 1.000” | 2.670 | 3.973 |
| #9 | 1.128” | 3.400 | 5.059 |
| #10 | 1.270” | 4.303 | 6.404 |
| #11 | 1.410” | 5.313 | 7.906 |
| #14 | 1.693” | 7.650 | 11.38 |
| #18 | 2.257” | 13.60 | 20.24 |
Bar number roughly corresponds to the bar’s diameter in eighths of an inch — a #5 bar is approximately 5/8” in diameter. Nominal weights per standard specification (ASTM A615/A706).
Metric Rebar Size Chart — Weight per Meter
| Diameter | Weight per meter (kg) | Weight per foot (lb, converted) |
|---|---|---|
| 6mm | 0.222 | 0.149 |
| 8mm | 0.395 | 0.266 |
| 10mm | 0.617 | 0.415 |
| 12mm | 0.888 | 0.597 |
| 16mm | 1.578 | 1.061 |
| 20mm | 2.466 | 1.658 |
| 25mm | 3.854 | 2.591 |
| 32mm | 6.313 | 4.244 |
| 40mm | 9.865 | 6.632 |
How to Calculate Rebar Weight
Total weight = Weight per foot (or meter) × Total length × Quantity
Worked example (US): 20 pieces of #5 rebar, each 10 ft long, for a slab: 1.043 lb/ft × 10 ft × 20 bars = 208.6 lbs.
Worked example (metric): 15 pieces of 12mm rebar, each 3m long, for a footing: 0.888 kg/m × 3m × 15 bars = 39.96 kg.
Rebar Weight for Slabs and Footings
Slab and footing rebar quantities come from a rebar schedule (spacing grid × slab dimensions), not just a single bar — once you know your total linear footage of rebar needed (from your spacing layout in both directions), enter that total directly into the calculator’s optional “total linear footage” field rather than calculating bar-by-bar. A typical residential slab uses #3 or #4 bar on a 12”–18” grid in both directions, though exact spacing depends on slab thickness, soil conditions, and local code — always follow your structural plans or a licensed engineer’s specification rather than a rule of thumb for load-bearing work.
Frequently Asked Questions
How do I calculate rebar weight?
Multiply the bar’s weight per foot (or per meter) by its total length and by the quantity of bars. A #5 bar (1.043 lb/ft), 10 ft long, times 20 bars equals 208.6 lbs total.
How much does a #4 rebar weigh per foot?
A #4 rebar weighs approximately 0.668 lb per foot (0.994 kg per meter) — see the full US bar-size chart above for #3 through #18.
How do I calculate rebar weight in kg?
Use the metric diameter chart (6mm–40mm) and multiply the weight-per-meter figure by your bar’s total length in meters, then by quantity. A 12mm bar, 3m long, weighs 0.888 × 3 = 2.664 kg per bar.
What does the rebar bar number (like #5) mean?
The bar number roughly corresponds to the bar’s diameter in eighths of an inch — a #5 bar is approximately 5/8” (0.625”) in diameter, a #8 bar is approximately 1” in diameter.
How much rebar weight do I need for a slab?
Total slab rebar weight comes from your rebar schedule — the spacing grid (commonly #3 or #4 bar on a 12”–18” grid for residential slabs) applied across the slab’s dimensions in both directions. Calculate your total linear footage from the schedule first, then multiply by the bar size’s weight per foot.
Does rebar weight vary by manufacturer?
Slightly — published weights are nominal figures per standard specification (ASTM A615 in the US), and actual mill tolerance can vary marginally. For structural design or a permitted project’s material takeoff, confirm exact figures against your supplier’s mill certification.
How do I convert rebar weight from pounds to kilograms?
Multiply pounds by 0.4536 to get kilograms, or use the metric chart above directly, which lists weight per meter in kg for standard metric bar diameters.
How much does a full piece of rebar weigh (20 ft or 6m stock length)?
Multiply the bar size’s weight per foot (or meter) by the standard stock length — a #5 bar in a standard 20 ft stock length weighs 1.043 × 20 = 20.86 lbs; a 12mm bar in a standard 6m length weighs 0.888 × 6 = 5.33 kg.
Can I download this as a spreadsheet or Excel calculator?
This page runs the calculation live in your browser — copy your results directly, or use the reference tables above to build your own spreadsheet with the standard weight-per-foot/meter figures.
Why does rebar weight matter for ordering?
Rebar is typically sold and priced by weight (per ton or per hundredweight), not by piece count — knowing total weight lets you get an accurate material quote and compare pricing between suppliers on a like-for-like basis.
Get free quotes from local concrete & foundation contractors
Rebar is priced by weight. Confirm mill figures and get contractor quotes before you order for a permitted pour.