Slab Thickness Calculator
Calculate minimum concrete slab thickness for deflection control based on ACI 318 requirements.
Slab Parameters
Recommended Slab Thickness
9.0"
(229 mm) | Span/Depth: 20.0
ACI Minimum
9.00"
Per Table 7.3.1.1
Effective Depth (d)
8.00"
h - cover - db/2
Loading
Self-Weight
112.5 psf
Total DL
127.5 psf
Live Load
40 psf
Factored Load (1.2D + 1.6L)
217.0 psf
Min Steel (As)
0.320
in²/ft
Temp & Shrink
0.194
in²/ft
Cost Estimate
$633.04/sf
Includes concrete, formwork, rebar
ACI 318 Minimum Thickness (Grade 60)
| Support Condition | One-Way Solid | Two-Way (approx) |
|---|---|---|
| Simply Supported | L/20 | L/30 |
| One End Continuous | L/24 | L/33 |
| Both Ends Continuous | L/28 | L/36 |
| Cantilever | L/10 | L/12 |
For fy other than 60,000 psi, multiply values by (0.4 + fy/100,000)