Concrete Mix Ratio Calculator (Sand, Gravel, Cement)
Enter your target concrete volume, pick a mix ratio, and get bags of cement plus volumes of sand and gravel. Ratios are by volume — the way field mixes are actually measured.
What each ratio is typically used for
| Ratio | Character | Typical use |
|---|---|---|
| 1 : 2 : 3 | General purpose | Paths, small slabs, posts, general repair |
| 1 : 2 : 4 | Standard / economical | Footings, fills, non-critical work |
| 1 : 1.5 : 3 | Stronger | Slabs, steps, surfaces needing durability |
| 1 : 3 : 4 | Lean | Bedding, blinding, mass fill |
Worked example: one cubic yard (27 ft³) of 1:2:3 concrete divides into 6 equal parts: 4.5 ft³ cement = 4.5 of the 94-lb bags (423 lb), 9 ft³ sand (0.33 yd³ ≈ 0.45 t), and 13.5 ft³ gravel (0.5 yd³ ≈ 0.71 t). Water goes in gradually — roughly half as much as cement by weight for a workable mix. In practice, mixes often run 5–6 bags per yard once yield loss is accounted for — the calculator gives the clean-ratio figure.
Related tools & guides
Concrete mix FAQ
What is the best concrete mix ratio?
For general-purpose work, 1:2:3 (cement : sand : gravel) is the common all-rounder; 1:2:4 suits non-critical fills and footings; 1:1.5:3 leans stronger for slabs and steps. Ratios are by volume. For structural concrete, use an engineered mix design instead of a rule-of-thumb ratio.
How many bags of cement for 1 cubic yard of concrete?
A 1:2:3 mix for one cubic yard (27 ft³) takes about 4.5 of the 94-pound bags of cement (4.5 ft³ of cement volume, 423 lb), plus roughly 9 ft³ of sand and 13.5 ft³ of gravel. Real-world mixes often run 5–6 bags per yard after yield loss. The calculator converts any target volume into all three.
Are the ratios by volume or weight?
By volume — shovel-to-shovel or bucket-to-bucket. That's how field mixes are actually measured. Weight-based mix designs are a different, more precise system used in engineered concrete.