Cement calculator
Mixing your own concrete for a 10 × 10 ft slab 4 in thick (with 10% extra) takes 9 bags of 94 lb Portland cement, 18 cu ft of sand and 27 cu ft of gravel, at 1 part cement to 2 of sand to 3 of gravel.
The mix
QUIKRETE's Portland cement data sheet gives a typical concrete mix by volume of 1 part Portland cement, 2 parts sand and 3 parts gravel, and says five to six 94 lb bags of cement make a cubic yard of concrete. A 94 lb bag of cement is about 1 cubic foot (Caltrans's maintenance tables give the same), so each bag goes with about 2 cu ft of sand and 3 cu ft of gravel. The calculator uses six bags a yard unless you choose otherwise.
10 ft × 10 ft × 4 in = 33.33 cu ft
9 bags × 1 cu ft: 9 cu ft cement, 18 cu ft sand, 27 cu ft gravel
The dry materials add up to more than the concrete they make, because the sand and cement fill the gaps between the stones once mixed with water. Add water a little at a time until the mix is workable but not soupy; too much water weakens it.
Cement, sand and gravel by volume of concrete
| Concrete | Bags of cement (5 to 6 a yard) | Sand, cu ft | Gravel, cu ft | Sand / gravel tons (at 6 bags) |
|---|---|---|---|---|
| 0.25 cu yd | 2 | 4 | 6 | 0.20 / 0.30 |
| 0.5 cu yd | 3 | 6 | 9 | 0.30 / 0.45 |
| 1 cu yd | 5 to 6 | 10 to 12 | 15 to 18 | 0.60 / 0.90 |
| 2 cu yd | 10 to 12 | 20 to 24 | 30 to 36 | 1.20 / 1.80 |
| 3 cu yd | 15 to 18 | 30 to 36 | 45 to 54 | 1.80 / 2.70 |
| 5 cu yd | 25 to 30 | 50 to 60 | 75 to 90 | 3.00 / 4.50 |
Mix your own or buy premixed bags?
Premixed bags of concrete already hold the cement, sand and gravel in the right proportions. Mixing your own pays when sand and gravel are delivered in bulk at a low price per ton; with bagged sand and gravel it usually costs more than premixed bags, as the calculator's cost shows at the default prices. Enter bulk prices per ton under Prices to compare.
| Item | Typical | Range | Stores |
|---|---|---|---|
| 94 lb bag of Portland cement | $17.92 | $15.00 to $23.99 | 11 |
| 50 lb bag of sand (about 0.5 cu ft) | $5.77 | $4.89 to $7.21 | 5 |
| 0.5 cu ft bag of gravel | $6.90 | $5.98 to $7.20 | 3 |
| 80 lb bag of concrete mix | $6.47 | $5.56 to $7.59 | 7 |
Sources
- QUIKRETE Portland Cement (Type I/II) data sheet, The QUIKRETE Companies, revised August 2022. Concrete mix by volume: 1 part Portland cement, 2 parts sand, 3 parts gravel; five to six 94 lb bags of cement make 1 cubic yard of concrete; mortar Type N 1:1:4¾–5¾ and Type S 1:½:3½–4½ (cement, lime, sand).
- Maintenance Manual Volume 1, Appendix: Useful Information, California Department of Transportation, July 2014. Loose weights of crushed gravel, limestone, granite, screenings, sand and soil; 111 lb of asphalt mix per square yard per inch; 2.0 tons per compacted cubic yard of base.
- QUIKRETE Concrete Mix (No. 1101) data sheet, The QUIKRETE Companies, revised October 2022. Bag yields: 40 lb 0.30 cu ft, 50 lb 0.375, 60 lb 0.45, 80 lb 0.60, 90 lb 0.675; about 140 lb per cubic foot; 2,500 psi at 7 days and 4,000 psi at 28 days; cure 5 days at 70 °F or warmer, 7 days at 50 to 70 °F; protect from freezing for the first 48 hours.
- Online store listings for bagged concrete, mortar, grout, block, rebar, mesh, gravel, sand, soil, mulch and pavers, Google Shopping results (Home Depot, Lowe's, Menards, Ace Hardware, Walmart and others), November 2026. Single-item prices by store; the calculators use the median as the default and show the range.