Rebar Calculator — Linear Feet for a Slab Grid
Enter your dimensions for an instant answer — the exact quantity to buy (waste included), a material cost, and an estimated installed cost. Change any figure to update the result live.
Your project
Standard size shown by default. Change any value — the answer recomputes instantly.
You need
344linear ft
Exact need: 312 linear ft · plus 10% waste allowance
Material cost
$223.6–$550.4
Installed (US avg)
$285–$633
Shopping list
| ITEM | QTY | PRICE RANGE |
|---|---|---|
| linear ft | 344 | $223.6–$550.4 |
| Estimated material total | $223.6–$550.4 |
Companion materials
- Grid: 13 + 13 bars at 12 in on-center
Material spec & worked example
Waste allowance
10%
Typical price
$0.65–$1.6 linear feet of #4 rebar
12 ft × 12 ft slab, 12 in grid: you need 312 linear ft (buy 344 with waste), about $223.6–$550.4 in materials. See how we calculate this →
Popular sizes
Installed cost by state
See a regionally-adjusted installed estimate — materials, labor, total.
View cost by state →Frequently asked
How much rebar for a concrete slab?
For a grid at the chosen spacing, add up the bars running each direction. A 12×12 slab on a 12-inch grid needs about 312 linear feet including laps.
What size rebar for a slab?
Residential slabs commonly use #3 or #4 (3/8" or 1/2") rebar on a 12–18 inch grid.