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Concrete Mix Ratio Calculator
Site-mix your own concrete. Enter cubic yards: get cement bags, sand, aggregate and water for a 1:2:4 mix.
Estimates only. Bag yields per manufacturer specs (80 lb ≈ 0.60 ft³, 60 lb ≈ 0.45 ft³, 40 lb ≈ 0.30 ft³). Ready-mix trucks carry ≈ 10 yd³. Always round up and confirm with your supplier.
A 1:2:4 site mix (one part cement, two sand, four aggregate) suits footings, slabs and general work. Enter your cubic yards below and the free mix ratio calculator lists cement bags, sand and aggregate volumes, plus approximate water.
How to use the concrete mix ratio calculator
- Enter the finished concrete volume in cubic yards.
- Read the cement bag count (94 lb bags).
- Read the sand and aggregate volumes in cubic yards.
- Use the water guide as a starting point and adjust for workability.
Formula
Dry volume ≈ wet volume × 1.52. Split 1:2:4 by volume: cement 1/7, sand 2/7, aggregate 4/7.
Practical tips
- One cubic yard of 1:2:4 needs about 7 bags of cement, 0.6 yd³ sand and 1.2 yd³ aggregate.
- Add water slowly: a soupy mix is weak when it cures.
- Mix at least 3 minutes after the last water goes in.
- Use clean water and aggregate: soil and clay ruin strength.
Frequently asked questions
What is a 1:2:4 concrete mix?
One part cement, two parts sand, four parts coarse aggregate by volume. A general-purpose site mix.
How much cement per cubic yard of 1:2:4?
About 7 bags of 94 lb cement per cubic yard of finished concrete.
Is site mix as strong as ready-mix?
It can be, with careful measuring and mixing. Ready-mix is more consistent for structural work.
Need volumes first? Try the slab calculator or browse the hub.
Worked examples
Example 1: 1 cubic yard of 1:2:4. 6 cement bags (94 lb), 0.44 yd3 sand, 0.88 yd3 aggregate, about 36 gallons water.
Example 2: 0.5 cubic yards. 3 cement bags, 0.22 yd3 sand, 0.44 yd3 aggregate, about 18 gallons water.
Mix materials table (1:2:4, dry factor 1.54)
| Concrete | Cement | Sand | Aggregate | Water |
|---|---|---|---|---|
| 0.5 yd3 | 3 bags | 0.22 yd3 | 0.44 yd3 | 18 gal |
| 1 yd3 | 6 bags | 0.44 yd3 | 0.88 yd3 | 36 gal |
| 2 yd3 | 12 bags | 0.88 yd3 | 1.76 yd3 | 72 gal |
| 5 yd3 | 30 bags | 2.20 yd3 | 4.40 yd3 | 180 gal |
More mix questions
What is a 1:2:4 concrete mix?
One part cement, two parts sand, four parts aggregate by volume. General-purpose mix for footings, slabs and walls.
Why is dry volume larger than wet volume?
Dry ingredients contain air voids that water fills, so you need about 1.54 times the finished volume in dry materials.