#4 slab bars
Common small slab planning lookup.
0.5 in diameter#4 rebarrebar size chart
Rebar Size Chart
U.S. rebar numbers roughly track eighths of an inch in diameter for common sizes, so #4 is about 1/2 inch and #5 is about 5/8 inch.
Inputs
Results
Immediate estimate#4 rebar0.5 in diameter0.668 lb/ft
Cross-sectional area0.2 sq in
Total length200 ft
Estimated weight133.6 lb
Selected bars10 bars at 20 ft
This is a size and weight lookup, not a reinforcement design, lap splice, spacing, or code compliance check.
Shopping list
- 10 bars #4 rebar — 133.6 lb estimated total weight.
Diagram
Rebar lookup
A selected bar size returns nominal diameter, area, weight, and order weight.
- Bar size
- Bar length
- Bar count
How this calculator works
Select a rebar size and bar count to look up nominal diameter, area, weight per foot, and estimated total weight.
Lookup model
The engine uses common nominal U.S. reinforcing bar diameter, area, and weight values for #3 through #11 bars.
Weight model
Total order weight is estimated by multiplying bar count, bar length, and nominal pounds per foot.
Design caution
This is a reference and material planning tool, not a reinforcement design, spacing, lap splice, or inspection check.
Lookup
match selected U.S. bar size to nominal diameter, area, and weightTotal length
bar length x bar countTotal weight
total length x nominal weight per footAssumptions
- U.S. bar sizes: Imperial deformed reinforcing bar sizes #3 through #11.
- Weight: Weight uses common nominal pounds per linear foot values.
Worked examples
#5 heavier reinforcement
Shows weight impact for a larger order.
0.625 in diameter#5 rebarFAQ
What size is #4 rebar?
#4 rebar is commonly treated as 1/2 inch nominal diameter.
What size is #5 rebar?
#5 rebar is commonly treated as 5/8 inch nominal diameter.
Can this tell me what rebar spacing to use?
No. Rebar spacing depends on the structural design, slab or wall loading, exposure, cover, and local requirements.
Sources and review
- Bar Identification, Concrete Reinforcing Steel Institute. Accessed 2026-07-20.
Reviewed 2026-07-20. Planning estimates only; confirm project-specific requirements.