#3 Rebar — Diameter, Weight & Area
Deformed reinforcing bar per ASTM A615 / A706
#3 rebar (also written No. 3 or number 3 bar) is 3/8" — 0.375 inches (9.53 mm) — in nominal diameter; the "3" stands for 3/8 of an inch. It weighs 0.376 pounds per foot (0.56 kg/m) with a nominal cross-section of 0.11 in² (71 mm²). A standard 20 ft bar weighs 7.5 lb, a 40 ft bar 15 lb.
These nominal values (per ASTM A615) are what reinforcement schedules, quotes, and delivery tickets use — the deformations are already accounted for in the nominal diameter.
#3 rebar: nominal cross-section drawn to scale (3/8" = 9.53 mm, A = 0.11 in²)Size & Weight
| Nominal diameter | 0.375 in (9.53 mm) |
| Nominal area | 0.11 in² (71 mm²) |
| Weight | 0.376 lb/ft (0.56 kg/m) |
Ordering Numbers
| 20 ft bar | 7.5 lb |
| 40 ft bar | 15 lb |
| Bars per US ton (20 ft) | 266 |
Frequently Asked Questions
What is the diameter of #3 rebar?
3/8", i.e. 0.375 inches or 9.53 mm — bar numbers count eighths of an inch, so #3 is nominally 3/8".
How thick is #3 rebar?
Number 3 bar is 3/8" thick (9.53 mm). That is the nominal diameter: the ribs are already included, because the nominal size is defined by mass per foot.
How much does #3 rebar weigh per foot?
0.376 lb per foot (0.56 kg/m). A 20 ft bar weighs 7.5 lb; a US ton is about 266 such bars.
What is the area of #3 rebar?
The nominal cross-section of #3 is 0.11 in² (71 mm²) — the value reinforcement schedules use when summing required steel area.
What is the metric equivalent of #3 rebar?
The closest European size is Ø10 (10 mm, 0.617 kg/m, B500 per EN 10080). Matches are approximate — when substituting, match the required steel area, not the bar count.
What grade is #3 rebar?
Grade is independent of size: ASTM A615 Grade 40, 60, or 75 (yield in ksi), with Grade 60 the US default. A706 covers weldable low-alloy bars for seismic work.
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