Concrete Mix Calculator
Calculate cement bags, sand, and gravel needed for any concrete mix ratio. Supports 1:2:3 standard, 1:1.5:3 strong, and 1:3:5 lean mixes with cost breakdown.
ft³
Cement Bags (94 lb)
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Sand (cubic feet) —
Gravel (cubic feet) —
Water (gallons) —
Extended More scenarios, charts & detailed breakdown ▾
ft³
Cement Bags (94 lb)
—
Sand (ft³) —
Gravel (ft³) —
Professional Full parameters & maximum detail ▾
ft³
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Quantities
Cement Bags (94 lb) —
Sand (ft³) —
Gravel (ft³) —
Water (gallons) —
Yield (ft³ per bag) —
Cost Breakdown
Cement Material Cost —
Sand Material Cost —
Gravel Material Cost —
Total Material Cost —
How to Use This Calculator
- Enter the total concrete volume in cubic feet.
- Select your mix ratio (standard 1:2:3 for general use, strong 1:1.5:3 for driveways).
- Results show cement bags, sand, and gravel needed.
- Use By Strength (PSI) to auto-select ratio by target strength.
- Use the Professional tab to add material costs and adjust the water-cement ratio.
Formula
Cement Volume = Total Volume × (C ÷ Total Parts) × 1.54
Cement Bags = Cement Volume (ft³) ÷ 0.45 ft³/bag
Water = Cement Weight (lbs) × w/c ratio ÷ 8.34 lb/gal
Example
Example: 27 ft³ (1 cubic yard), 1:2:3 standard mix. Cement = 27 × (1/6) × 1.54 = 6.93 ft³ → 15.4 bags. Sand = 27 × (2/6) × 1.54 = 13.86 ft³. Gravel = 20.79 ft³.
Frequently Asked Questions
- A 1:2:3 mix uses 1 part cement, 2 parts sand, and 3 parts gravel/aggregate by volume. This produces approximately 3,000 PSI concrete, suitable for most general construction including slabs, footings, and walls.
- A standard 1:2:3 mix requires approximately 6–7 bags of 94 lb cement per cubic yard (27 cubic feet). This calculator shows bags per cubic foot based on your selected volume.
- The water-cement ratio (w/c) is the weight of water divided by the weight of cement. Lower ratios (0.40) produce stronger, more durable concrete. Higher ratios (0.60+) weaken the mix. Most structural concrete uses 0.40–0.50.
- Use a 1:1.5:3 strong mix (4000 PSI) for driveways and high-traffic areas. For sidewalks and patios, a 1:2:3 standard mix (3000 PSI) is sufficient. Lean 1:3:5 mix is only for low-load fill applications.
- Fresh concrete components occupy more volume than the mixed result due to voids. The 1.54 factor means you need 1.54 cubic feet of dry materials to produce 1 cubic foot of concrete after compaction.