How much rebar for a 10×10 slab?
Quick Answer
A 10×10 foot slab with #4 rebar on 12-inch centers requires 11 bars running each direction — 22 bars total — at 10 feet each, totaling 220 linear feet of rebar. At typical pricing of $0.60–0.90 per linear foot for #4 rebar, that's $130–200 in rebar materials.
Quick Reference Table
| Slab Size | Rebar (12" spacing, #4) |
|---|---|
| 10×10 ft | 220 lin ft / 22 bars |
| 12×12 ft | 312 lin ft / 26 bars |
| 10×20 ft | 330 lin ft / 33 bars |
| 20×20 ft | 840 lin ft / 42 bars |
| 20×30 ft | 1,240 lin ft / 62 bars |
| 24×24 ft | 1,200 lin ft / 50 bars |
How to Calculate It Yourself
- 1
Choose spacing: residential slabs typically use #4 rebar on 12-inch centers. Driveways and heavier loads use 12" or 8" spacing with #4 or #5 bar.
- 2
Calculate bars per direction: divide slab length by spacing and add 1. For 10 ft on 12" centers: 10 ÷ 1 + 1 = 11 bars per direction.
- 3
Calculate total bars: 11 bars × 2 directions = 22 bars. Each bar is 10 ft long = 220 linear feet total.
- 4
Add 10% for overlap and waste: 220 × 1.10 = 242 linear feet. Round up when ordering.
Pro Tip
Rebar comes in 20-foot sticks. For a 10×10 slab, each 20-foot stick cuts perfectly in half with zero waste. Order 12 sticks (240 lin ft) to cover 22 bars × 10 ft with waste.
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