US Rebar Size Chart — #3 to #18
Deformed reinforcing bars per ASTM A615 / A706
Every standard US bar number from #3 (0.375", 0.376 lb/ft) to #18 (2.257", 13.6 lb/ft). The bar number counts eighths of an inch of nominal diameter — a #5 is 5/8". Click a size for the full page with bar weights, tons, and the closest metric equivalent.
US rebar — #3 to #18
| Bar | d (in) | d (mm) | A (in²) | lb/ft | kg/m |
|---|---|---|---|---|---|
| #3 | 0.375" | 9.53 | 0.11 | 0.376 | 0.56 |
| #4 | 0.5" | 12.7 | 0.2 | 0.668 | 0.994 |
| #5 | 0.625" | 15.88 | 0.31 | 1.043 | 1.552 |
| #6 | 0.75" | 19.05 | 0.44 | 1.502 | 2.235 |
| #7 | 0.875" | 22.23 | 0.6 | 2.044 | 3.042 |
| #8 | 1" | 25.4 | 0.79 | 2.67 | 3.973 |
| #9 | 1.128" | 28.65 | 1 | 3.4 | 5.06 |
| #10 | 1.27" | 32.26 | 1.27 | 4.303 | 6.404 |
| #11 | 1.41" | 35.81 | 1.56 | 5.313 | 7.907 |
| #14 | 1.693" | 43 | 2.25 | 7.65 | 11.38 |
| #18 | 2.257" | 57.33 | 4 | 13.6 | 20.24 |
Frequently Asked Questions
How do rebar numbers work?
The number is the nominal diameter in eighths of an inch: #4 = 4/8 = 1/2", #8 = 1". From #9 up the diameters correspond to the round dimensions of old square bars, so they are slightly irregular (#9 = 1.128").
What grade is standard US rebar?
ASTM A615 Grade 60 (60 ksi ≈ 420 MPa yield) is the default; Grade 40 appears in light work and Grade 75/80 in heavy construction. A706 covers weldable, seismic-ductile bars. Size and weight are the same across grades.
What are metric equivalents of US bar sizes?
Approximate pairs: #3 ≈ Ø10, #4 ≈ Ø12, #5 ≈ Ø16, #6 ≈ Ø20, #8 ≈ Ø25, #10 ≈ Ø32. Matches are inexact — when substituting, match the required steel area rather than the bar count.
Values are entered from the governing standard’s published tables and cross-checked programmatically against its mass and section formulas before publication. Spotted an error? Write to advertising@metalabout.net — verified corrections ship within days. About