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Concrete Mix Ratio
A ratio is cement to sand to stone by volume. Enter the wet concrete you need to place. The batch is the loose materials that make it.
Nominal mixes are measured by volume: cement, then sand, then stone.
Quick answer
Concrete Mix Ratio: 1:2:4 means 1 part cement, 2 sand, 4 stone by volume. Dry materials use a 1.54 voids factor. A 94 lb bag of portland cement counts as 1 ft³. One cubic yard of 1:2:4 needs about 5.9 bags of cement, ~0.44 yd³ sand, and ~0.88 yd³ stone.
Concrete Mix Ratio: What the ratio is — and is not
Nominal ratios are batch recipes by bucket. They are not a 3,000 psi or 25 MPa guarantee. If the drawing names a strength, order that mix from the plant. Use a ratio when someone actually specified one — or when you are practicing site batching on a small pour that does not need a certified mix.
Search volume on “concrete mix ratio” is huge. Most pages stop at listing 1:2:4. Concrete Calculator turns the ratio into bags and aggregate yards after you know wet volume from the slab or yard calculator.
Worked batch: 1 yd³ of 1:2:4
Wet volume 27 ft³ scales to about 41.6 ft³ dry with the 1.54 factor. Parts total 1+2+4 = 7, so cement is 41.6 × 1/7 ≈ 5.9 ft³ ≈ 6 bags of 94 lb cement after rounding. Sand takes two parts; stone takes four.
- Wet 27 ft³ → dry 41.6 ft³
- Cement 5.9 ft³ ≈ 6 bags (94 lb)
- Sand 11.9 ft³ ≈ 0.44 yd³
- Stone 23.8 ft³ ≈ 0.88 yd³
- Water start ~5–6 gal per cement bag
Other ratios on Concrete Calculator
Leaner mixes use more aggregate per cement; richer mixes reverse that. Pick the preset that matches the note on your sketch, then scale to the wet yards you already calculated.
- 1:3:6 lean / mass fill
- 1:2:3 richer general
- 1:1.5:3 richer structural nominal
- 1:1:2 rich patching (expensive)
Water and workability
A starting range of about 5–6 gallons per 94 lb cement bag is a planning hint. Less water if the mix already places. More water weakens the paste. For deep ratio notes see mix ratios explained and the 1:2:4 mix guide.
Standard concrete mix ratio vs plant designs
“Standard concrete mix ratio” in search usually means a nominal 1:2:4 or regional classroom ratio. Plant designs are weighed recipes with admixtures and a target strength. If your permit or engineer named a strength, the plant ticket wins. If a sketch literally says 1:2:4, this calculator turns that note into bags and aggregate.
Concrete mixture ratio and concrete mix calculator queries often want the same three-part volume recipe. Concrete Calculator keeps cement : sand : stone visible, applies 1.54 for dry volume, and scales to the wet yards you already measured.
1:2:4 concrete mix calculator — half and double batches
Half a wet yard needs about 3 cement bags after rounding, ~0.22 yd³ sand, and ~0.44 yd³ stone. Double a yard and you are in ready-mix territory for most crews — see the 1:2:4 mix guide for the per-yard sheet you can print.
Related tools
Get wet volume from the slab or yard calculator first.
Frequently asked questions
What is a 1:2:4 concrete mix?
1 cement : 2 sand : 4 stone by volume — a common nominal general-purpose mix.
How many cement bags per yard of 1:2:4?
About 5.9 bags of 94 lb cement with the 1.54 dry factor.
How much water?
About 5–6 gallons per 94 lb bag as a start. Less water if it already places.
M20 / M25 / psi mixes?
Order the specified strength. Do not assume a ratio equals that grade.
Is concrete ratio the same as mix ratio?
Yes in search — cement : sand : stone by volume.