Concrete Mix Ratios: Cement, Sand, Gravel and Water Per Yard
Part of the project planner: Planning a concrete patio, slab or driveway.
The classic mix is 1 part cement, 2 parts sand and 4 parts gravel by volume, with enough water to make it workable. A cubic yard of 1:2:4 concrete needs about 6 bags of 94 lb cement, 11.9 cubic feet of sand, 23.8 cubic feet of gravel and about 33 gallons of water. The concrete mix calculator does your own volume.
Mix ratios and quantities per cubic yard
No waste added. A 94 lb bag of cement is about 1 cubic foot, and the dry materials take up about 1.54 times the finished volume:
| Mix (cement : sand : gravel) | Use | Cement bags (94 lb) | Sand (ft³) | Gravel (ft³) | Water (gal) |
|---|---|---|---|---|---|
| 1 : 1½ : 3 | Strong: structural work, 4,000 psi and up | 8 | 11.3 | 22.7 | 43 |
| 1 : 2 : 3 | Strong: footings, columns, slabs under load | 7 | 13.9 | 20.8 | 39 |
| 1 : 2 : 4 | General purpose: paths, patios, about 3,000 psi | 6 | 11.9 | 23.8 | 33 |
| 1 : 3 : 5 | Lean: fill and bases, not for exposed work | 5 | 13.9 | 23.1 | 26 |
Mixing it yourself
- Use the same bucket or shovel count for each part, so the ratio holds.
- Mix the dry cement and sand first, add the gravel, and then the water a little at a time.
- Keep the mix stiff enough to hold a shape, and no wetter than it needs to be to place it. Extra water weakens the concrete.
- Use clean, sharp sand and clean gravel. Dirty aggregates weaken concrete.
- Mix only what you can place in about an hour.
Mix or buy?
A cubic yard of concrete is a lot of hand mixing: about 6 bags of cement plus the sand and gravel, in batches of a few cubic feet. A quarter of a yard takes 2 bags of cement, 3.0 cubic feet of sand and 5.9 cubic feet of gravel. For more than that, buy bagged mix (80 lb bags, 0.6 cubic feet each) for small jobs or order ready-mix by the cubic yard. See the bags of concrete guide.
Curing
Concrete gains strength by reacting with water, not by drying. Keep it damp or covered for about a week, protect it from frost, and keep traffic off it for a week or more. Estimates only: structural concrete needs a design from an engineer.
Frequently asked questions
What is the best concrete mix ratio?
1 part cement, 2 parts sand and 4 parts gravel (1:2:4) is the general-purpose mix for paths, patios and small slabs, at roughly 3,000 psi. Use 1:2:3 or 1:1½:3 where you need more strength.
How many bags of cement per cubic yard of concrete?
About 6 bags of 94 lb for a 1:2:4 mix (no waste), with 11.9 cubic feet of sand and 23.8 cubic feet of gravel.
How much water do I add?
About 33 gallons per cubic yard at a water-to-cement ratio of 0.5 by weight. Use less if the sand is damp: less water gives stronger concrete.
Is it cheaper to mix my own concrete?
Only for small amounts or if you can buy the sand and gravel in bulk. Beyond about a cubic yard, ready-mix delivery is faster and gives a more consistent product. A quarter yard takes about 2 bags of cement.
What does the 94 lb bag of cement make?
A 94 lb bag of Portland cement is about one cubic foot, and is the "1 part" in the ratio. A bag of ready-mixed concrete (80 lb) makes about 0.6 cubic feet.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.