How much concrete do I need for a 10×10 slab?
For a 10×10 slab at 4 inches thick, you need 1.23 cubic yards. At 6 inches thick, you need 1.85 yards. Use the slab calculator for exact dimensions and waste factors.
Concrete Tools / Concrete Calculators & Estimating Guide (All Projects)
How to Estimate Concrete (Calculators for Every Project)
Updated February 2026
To estimate concrete, calculate volume in cubic feet (length × width × thickness) and divide by 27 to get cubic yards. A typical 12×10 slab at 4 inches thick needs 1.5 yards. Add 5–10% for waste.
This guide provides calculators for slabs, driveways, footings, walls, columns, and foundations. Each calculator handles standard waste factors, converts to bag counts, and estimates rebar needs so you can plan materials before ordering ready-mix or buying bags.
For cost planning, see the concrete cost per yard guide. For mix ratios and strength specs, see the concrete mix ratio guide.
Related tools
Common Concrete Project Estimates
| Project Type | Typical Dimensions | Thickness | Est. Cubic Yards | Calculator |
|---|---|---|---|---|
| Small patio | 10×12 ft | 4 in | 1.5 yards | Patio calculator |
| Single-car driveway | 10×20 ft | 4 in | 2.5 yards | Driveway calculator |
| Garage slab | 20×20 ft | 4 in | 5 yards | Slab calculator |
| Sidewalk (50 ft) | 50×3 ft | 4 in | 1.9 yards | Slab calculator |
| Foundation wall (40 ft) | 40 ft × 8 ft × 8 in | 8 in | 7.4 yards | Wall calculator |
| Post holes (10 posts) | 12 in diameter × 3 ft deep | — | 0.9 yards | Post hole calculator |
Note: Add 5–10% waste to all estimates.
Frequently Asked Questions
How do I convert cubic feet to cubic yards?
Divide cubic feet by 27. Measure length × width × thickness in feet, multiply them to get cubic feet, then divide by 27.
Should I order ready-mix or use bags?
Order ready-mix for projects over 1 cubic yard (about 40–50 bags). Use bagged concrete for small repairs or post holes.
How much does concrete cost per yard?
Ready-mix concrete typically costs $125–$175 per cubic yard nationally. See the concrete cost per yard guide for regional pricing.
Do I need a gravel base under concrete?
Most slabs, patios, and driveways require 4–6 inches of compacted gravel for drainage and stability.
Most Used Concrete Calculators
Concrete Slab Calculator
Slab volume with waste and bag estimates.
Concrete Driveway Calculator
Driveway yardage for ordering ready-mix.
Concrete Patio Calculator
Patio pours with thickness and waste factors.
Concrete Footing Calculator
Footing volumes for posts and small structures.
Concrete Foundation Wall Calculator
Foundation wall yardage with consistent thickness.
Structural Concrete Calculators
Concrete Wall Calculator
Wall volume based on height, length, and thickness.
Concrete Column Calculator
Round or square column yardage.
Concrete Beam Calculator
Beam volume for structural pours.
Retaining Wall Calculator
Retaining wall volume with core dimensions.
Concrete Ramp Calculator
Ramp volume by slope and landing size.
Concrete Stoop Calculator
Stoop volume with risers and platform.
Concrete Steps Calculator
Steps volume for entry and stair runs.
Sonotube Calculator
Cylindrical pier volumes from tube size.
Post Hole Concrete Calculator
Post hole volume for fencing and decks.
Concrete Material & Reinforcement Tools
Rebar Estimator
Quick takeoffs for slab and wall reinforcement.
Gravel Base Calculator
Subbase volume for slabs and driveways.
Concrete Bag Calculator
Bags needed by size with waste baked in.
Concrete Yardage Calculator
Convert dimensions to cubic yards fast.
Concrete Curing Time Calculator
Cure timeline for finishing and load planning.
How to Estimate Concrete (Quick Formula)
Cubic Yards = (Length × Width × Thickness in feet) ÷ 27
Example: 12 ft × 10 ft slab at 4 in (0.33 ft) thick = 12 × 10 × 0.33 ÷ 27 ≈ 1.47 cubic yards.
When to Use Each Calculator
- Slabs & patios → slab calculator.
- Driveways → driveway calculator.
- Walls & foundations → wall calculator or foundation calculator.
- Posts & piers → sonotube calculator or post hole calculator.
- Reinforcement planning → rebar estimator.
- Subbase prep → gravel base calculator.