How to use Rebar Weight Calculator
- Choose the material grade, or enter a custom density.
- Pick the shape and enter dimensions. Pipe can use size and schedule, sheet can use gauges, rebar uses bar sizes and beams can come from the standard section library.
- Enter length and quantity, optionally a unit price; results update as you type. Add several items to the list to total an order.
Rebar weight chart
Metric rebar weight per metre = 0.00617 × d² (nominal diameter in mm), often written as d²/162. US bars use ASTM A615 nominal weights; Canadian bars use CSA G30.18.
| Diameter mm | Area mm² | kg/m | Metres per tonne | kg per 12 m bar |
|---|---|---|---|---|
| 6 | 28.3 | 0.222 | 4,505.4 | 2.66 |
| 8 | 50.3 | 0.395 | 2,534.3 | 4.74 |
| 10 | 78.5 | 0.617 | 1,622 | 7.4 |
| 12 | 113.1 | 0.888 | 1,126.4 | 10.65 |
| 14 | 153.9 | 1.208 | 827.5 | 14.5 |
| 16 | 201.1 | 1.578 | 633.6 | 18.94 |
| 18 | 254.5 | 1.998 | 500.6 | 23.97 |
| 20 | 314.2 | 2.466 | 405.5 | 29.59 |
| 22 | 380.1 | 2.984 | 335.1 | 35.81 |
| 25 | 490.9 | 3.853 | 259.5 | 46.24 |
| 28 | 615.8 | 4.834 | 206.9 | 58 |
| 32 | 804.2 | 6.313 | 158.4 | 75.76 |
| 36 | 1,017.9 | 7.99 | 125.2 | 95.88 |
| 40 | 1,256.6 | 9.865 | 101.4 | 118.38 |
| 50 | 1,963.5 | 15.413 | 64.9 | 184.96 |
| Bar size | Diameter | lb/ft | kg/m | lb per 20 ft bar |
|---|---|---|---|---|
| #3 | 0.375" / 9.5 mm | 0.376 | 0.56 | 7.5 |
| #4 | 0.5" / 12.7 mm | 0.668 | 0.994 | 13.4 |
| #5 | 0.625" / 15.9 mm | 1.043 | 1.552 | 20.9 |
| #6 | 0.75" / 19 mm | 1.502 | 2.235 | 30 |
| #7 | 0.875" / 22.2 mm | 2.044 | 3.042 | 40.9 |
| #8 | 1" / 25.4 mm | 2.67 | 3.973 | 53.4 |
| #9 | 1.128" / 28.7 mm | 3.4 | 5.06 | 68 |
| #10 | 1.27" / 32.3 mm | 4.303 | 6.404 | 86.1 |
| #11 | 1.41" / 35.8 mm | 5.313 | 7.907 | 106.3 |
| #14 | 1.693" / 43 mm | 7.65 | 11.384 | 153 |
| #18 | 2.257" / 57.3 mm | 13.6 | 20.239 | 272 |
| Bar size | Diameter mm | kg/m | Metres per tonne |
|---|---|---|---|
| 10M | 11.3 | 0.785 | 1,273.9 |
| 15M | 16 | 1.57 | 636.9 |
| 20M | 19.5 | 2.355 | 424.6 |
| 25M | 25.2 | 3.925 | 254.8 |
| 30M | 29.9 | 5.495 | 182 |
| 35M | 35.7 | 7.85 | 127.4 |
| 45M | 43.7 | 11.775 | 84.9 |
| 55M | 56.4 | 19.625 | 51 |
Frequently asked questions
Where does the d²/162 rebar formula come from?
Weight per metre = π/4 × d² × 7850 ÷ 10⁶ = 0.006165 × d² ≈ d²/162.2 (d in mm, result in kg/m). A 16 mm bar is 1.578 kg/m.
Does the slab estimate include laps and hooks?
The estimate counts bars both ways within the cover at the given spacing. Laps, hooks and chairs are not modelled separately; allow for them in the waste percentage (typically 3–8%) and use the bar bending schedule for final quantities.
What is the formula for metal weight?
Weight = cross-sectional area × length × density. With millimetres and g/cm³, weight per metre in kg/m = area (mm²) × density ÷ 1000. A Ø20 mm steel bar has 314.16 mm², so 314.16 × 7.85 ÷ 1000 = 2.466 kg/m.
Why does theoretical weight differ from scale weight?
Theoretical weight uses nominal dimensions. Delivered material has thickness or wall tolerances, rolled radii, galvanizing and coatings, typically ±2–5%. State in the contract whether you settle by theoretical or actual weight.
Can I use inches and pounds?
Yes. Switch to inches for dimensions; results always show kg, lb, kg/m and lb/ft. Length can be m, mm, ft or in, and price can be per kg, lb, tonne, metre, foot or piece.
Can I total several items?
Use “Add to list” to collect different materials, shapes and quantities. The list totals weight and cost and can be copied or exported as CSV for quotations and container planning. It is stored only in this browser.
Theoretical weights use nominal dimensions and densities for quoting, shipping and cutting estimates. Settlement weight follows the contract, mill certificate or actual weighing.