Rebar Size Converter
Look up rebar bar numbers and their diameter in inches, millimeters, and cross-sectional area.
Select a bar size for full details.
Select a rebar size — see diameter, area, and weight details.
Rebar Details
Rebar (reinforcing bar) sizes use a numbering system based on diameter.
US bar sizes (imperial):
- Bar number = diameter in 1/8 inch increments
- Example: #4 bar = 4/8 inch = 0.5 inches diameter
Common rebar sizes:
| Bar # | Diameter (in) | Diameter (mm) | Area (in2) | Weight (lb/ft) |
|---|---|---|---|---|
| #3 | 0.375 | 9.525 | 0.11 | 0.376 |
| #4 | 0.500 | 12.700 | 0.20 | 0.668 |
| #5 | 0.625 | 15.875 | 0.31 | 1.043 |
| #6 | 0.750 | 19.050 | 0.44 | 1.502 |
| #7 | 0.875 | 22.225 | 0.60 | 2.044 |
| #8 | 1.000 | 25.400 | 0.79 | 2.670 |
| #9 | 1.128 | 28.651 | 1.00 | 3.400 |
| #10 | 1.270 | 32.258 | 1.27 | 4.303 |
| #11 | 1.410 | 35.814 | 1.56 | 5.313 |
Metric rebar uses the diameter in mm directly (e.g., 10M = 10 mm).