#9 Rebar — Diameter, Weight & Area
Deformed reinforcing bar per ASTM A615 / A706
#9 rebar (also written No. 9 or number 9 bar) is 1.128" — 1.128 inches (28.65 mm) — in nominal diameter; the "9" stands for 9/8 of an inch. It weighs 3.4 pounds per foot (5.06 kg/m) with a nominal cross-section of 1 in² (645 mm²). A standard 20 ft bar weighs 68 lb, a 40 ft bar 136 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.
#9 rebar: nominal cross-section drawn to scale (1.128" = 28.65 mm, A = 1 in²)Size & Weight
| Nominal diameter | 1.128 in (28.65 mm) |
| Nominal area | 1 in² (645 mm²) |
| Weight | 3.4 lb/ft (5.06 kg/m) |
Ordering Numbers
| 20 ft bar | 68 lb |
| 40 ft bar | 136 lb |
| Bars per US ton (20 ft) | 29 |
Frequently Asked Questions
What is the diameter of #9 rebar?
1.128", i.e. 1.128 inches or 28.65 mm — bar numbers count eighths of an inch, so #9 is nominally 9/8".
How thick is #9 rebar?
Number 9 bar is 1.128" thick (28.65 mm). That is the nominal diameter: the ribs are already included, because the nominal size is defined by mass per foot.
How much does #9 rebar weigh per foot?
3.4 lb per foot (5.06 kg/m). A 20 ft bar weighs 68 lb; a US ton is about 29 such bars.
What is the area of #9 rebar?
The nominal cross-section of #9 is 1 in² (645 mm²) — the value reinforcement schedules use when summing required steel area.
What is the metric equivalent of #9 rebar?
The closest European size is Ø28 (28 mm, 4.83 kg/m, B500 per EN 10080). Matches are approximate — when substituting, match the required steel area, not the bar count.
What grade is #9 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