How Much Concrete for a 10x10 Slab?
For a 10x10 slab (100 sq ft), you typically need 1.23 cubic yards at 4 inches, 1.54 cubic yards at 5 inches, or 1.85 cubic yards at 6 inches before waste. Most crews add 5-10% waste depending on forms and subgrade.
Quick 10x10 slab table
| Thickness | Cubic Feet | Cubic Yards | 80 lb Bags (approx.) |
|---|---|---|---|
| 4 in | 33.3 | 1.23 | 56 |
| 5 in | 41.7 | 1.54 | 70 |
| 6 in | 50.0 | 1.85 | 84 |
How to calculate concrete for a 10x10 slab
Convert thickness to feet first. Example: 4 inches / 12 = 0.333 ft. Then multiply length x width x depth: 10 x 10 x 0.333 = 33.3 cubic feet. Finally divide by 27 to convert to cubic yards: 33.3 / 27 = 1.23 yards. This is the same method used in supplier estimates and dispatch calls.
How much extra concrete should you order?
Use 5% extra for straight, well-prepared forms. Use 10% extra when the base is uneven, forms are complex, or access is tight. Ordering too little can force a second short-load fee and delay finishing.
Bags vs ready-mix for 10x10 slabs
At 4 inches, a 10x10 slab needs about 56 bags of 80 lb mix. At 6 inches, around 84 bags. For most full slabs, ready-mix is faster and more consistent; bag mix is better for small pads and repairs.
Field checklist before ordering
- Measure inside forms, not outside. Outside dimensions can overstate concrete needed.
- Confirm slab thickness by use. Patios and sidewalks differ from garage slab requirements.
- Separate base material from concrete. Use the gravel calculator for compacted base stone.
Reviewed: May 20, 2026 by YardsCalculator editorial team.