Rebar Calculator
Ten bars of 12 mm rebar, each 12 m long, weigh 106.54 kg. That is 0.11 tonnes and 234.9 lb. One meter of 12 mm bar is 0.888 kg.
Last updated . Steel density is 7,850 kg/m³. Diameter starts at 12 mm. Length starts at 12 m. The count starts at 10.
Convert a rebar size, a cut length, and a piece count into kilograms, tonnes, and pounds. Metric bars from 6 mm to 32 mm and US sizes #3 through #11, #14, and #18 are on the menu. There is no standard #12, #13, or #15 through #17. Length accepts meters, feet, centimeters, inches, and millimeters.
Concrete volume is on the concrete calculator, the slab calculator, and the footing calculator. This page is the steel weight only. Plate, pipe, angle, and beam weight are on the steel weight calculator. Mesh sheets are on the wire mesh calculator.
Rebar weight
kg/m = (π ÷ 4) × (diameter in meters)² × 7850. The field shortcut d² ÷ 162, with d in millimeters, is the same steel density rounded. This tool uses 7850 kg/m³.
Results
How much does the rebar weigh?
A round bar’s weight is the area of the circle times the length times the density of steel. With the diameter in meters, kilograms per meter = (π ÷ 4) × diameter² × 7,850. Ten pieces at 12 m are 120.00 m, and 120.00 × 0.888 kg/m = 106.54 kg.
The shop formula d² ÷ 162 uses the diameter in millimeters and rounds the same density. For 12 mm it prints 0.889 kg/m. This tool keeps 7,850 kg/m³ and prints 0.888 kg/m. The difference on the ten-bar example is about 0.1 kg.
Bar weight
Every row is the tool’s figure at 7,850 kg/m³. Pounds per foot are kilograms per meter × 2.2046226218 ÷ 3.280839895.
| Bar | Diameter | kg/m | lb/ft |
|---|---|---|---|
| 6 mm | 6 mm | 0.222 | 0.149 |
| 8 mm | 8 mm | 0.395 | 0.265 |
| 10 mm | 10 mm | 0.617 | 0.414 |
| 12 mm | 12 mm | 0.888 | 0.597 |
| 14 mm | 14 mm | 1.208 | 0.812 |
| 16 mm | 16 mm | 1.578 | 1.061 |
| 18 mm | 18 mm | 1.998 | 1.342 |
| 20 mm | 20 mm | 2.466 | 1.657 |
| 22 mm | 22 mm | 2.984 | 2.005 |
| 25 mm | 25 mm | 3.853 | 2.589 |
| 28 mm | 28 mm | 4.834 | 3.248 |
| 32 mm | 32 mm | 6.313 | 4.242 |
| #3 | 3/8 in | 0.559 | 0.376 |
| #4 | 1/2 in | 0.994 | 0.668 |
| #5 | 5/8 in | 1.554 | 1.044 |
| #6 | 3/4 in | 2.237 | 1.503 |
| #7 | 7/8 in | 3.045 | 2.046 |
| #8 | 1 in | 3.978 | 2.673 |
| #9 | 1.128 in | 5.061 | 3.401 |
| #10 | 1.270 in | 6.416 | 4.311 |
| #11 | 1.410 in | 7.908 | 5.314 |
| #14 | 1.693 in | 11.401 | 7.661 |
| #18 | 2.257 in | 20.262 | 13.616 |
Rows added to the chart, using the same 7,850 kg/m³ math, are 6 mm, 14 mm, 18 mm, 22 mm, 28 mm, 32 mm, and US #7, #8, #9, #10, #11, #14, and #18. Nominal diameters from #9 up are the ASTM sizes: #9 is 1.128 in, #10 is 1.270 in, #11 is 1.410 in, #14 is 1.693 in, and #18 is 2.257 in. There is no standard #12, #13, or #15 through #17.
Worked example
Leave the size at 12 mm, the length at 12 m, and the count at 10. Weight per meter reads 0.888 kg/m. Weight per foot reads 0.597 lb/ft. Total length reads 120.00 m. Total weight reads 106.54 kg, 0.11 t, and 234.9 lb.
Frequently asked questions
How much does rebar weigh?
Weight depends on the diameter. At 7,850 kg/m³, 8 mm is 0.395 kg/m, 10 mm is 0.617 kg/m, 12 mm is 0.888 kg/m, 16 mm is 1.578 kg/m, 20 mm is 2.466 kg/m, and 25 mm is 3.853 kg/m. A #4 bar, 1/2 inch, is 0.668 lb/ft.
What is the formula for rebar weight?
Kilograms per meter = (π ÷ 4) × (diameter in meters)² × 7,850. The site shortcut d² ÷ 162, with d in millimeters, is that density rounded: 12² ÷ 162 = 0.889 kg/m, and the tool’s 7,850 kg/m³ figure is 0.888 kg/m. Multiply by the total length.
How much do 10 bars of 12 mm weigh?
Leave the size at 12 mm, the length at 12 m, and the count at 10. Total length is 120.00 m. Total weight is 106.54 kg, 0.11 tonnes, and 234.9 lb. One bar of that length is 10.65 kg.
How much does #4 rebar weigh per foot?
A #4 bar is 1/2 inch in diameter, 12.7 mm. The tool shows 0.668 lb/ft and 0.994 kg/m. Twenty bars at 20 ft each are 400 feet, 267.3 lb, and 121.24 kg. Switch the size menu to #4 and the length unit to feet to see it.
How many tonnes of steel is that?
Divide kilograms by 1,000. The ten 12 m bars of 12 mm are 0.11 tonnes. One hundred of those same bars would be 1.07 tonnes. A short ton is 2,000 lb, so 234.9 lb is 0.12 short tons. Yards of concrete are a separate order, on the concrete calculator.
Does the bar weight include laps and hooks?
Only if you type the cut length, hooks included. A 40-diameter lap on a 12 mm bar is 480 mm, about 0.48 m, and 0.888 kg/m makes that lap 0.43 kg per splice. Add the lap to the piece length before you multiply by the count. This page does not look up a spacing schedule. Which bar that spacing belongs to, and why a 12 mm bar is not #4, is the rebar sizes chart.
Is 7,850 the right steel density?
Yes for carbon reinforcing bar. It is the density behind both d²/162 and the US pounds-per-foot tables. A #5 bar comes out at 1.044 lb/ft. If a mill certificate quotes a different density, scale the kilograms by that number divided by 7,850.
What do 6 mm, #9, #14, and #18 weigh?
A 6 mm bar is 0.222 kg/m and 0.149 lb/ft. ASTM sizes skip #12, #13, and #15 through #17. #9 is 1.128 in, 5.061 kg/m and 3.401 lb/ft. #14 is 1.693 in, 11.401 kg/m and 7.661 lb/ft. #18 is 2.257 in, 20.262 kg/m and 13.616 lb/ft. The 12 mm example is unchanged: ten bars at 12 m are still 106.54 kg.