Concrete Mix Ratio Calculator
Accurately calculate the exact amount of Portland cement, sand, and gravel needed to mix custom concrete.
Mix Specifications
Materials Required
Concrete Mix Ratios Reference
M10 = 1 : 3 : 6 (Cement : Sand : Aggregate)
M15 = 1 : 2 : 4
M20 = 1 : 1.5 : 3
M25 = 1 : 1 : 2
M30 = 1 : 0.75 : 1.5
For estimation purposes only. Verify structural calculations with a licensed engineer.
Cement Mixing Calculator
While most DIYers buy pre-mixed bags of concrete at the hardware store, large-scale projects can be completed much cheaper by mixing the raw ingredients from scratch. To do this successfully, you need a precise concrete mix ratio calculator.
Concrete is not a single materialit is a recipe. The strength, durability, and workability of the final product depend entirely on the precise ratio of Portland cement, sand, and gravel (aggregate). If you add too much sand, the concrete becomes weak. If you add too much gravel, it becomes unworkable and full of "honeycomb" voids. Our cement sand stone ratio calculator ensures your recipe is perfectly balanced.
The 1 2 3 Concrete Mix Ratio
The most universally accepted standard for mixing general-purpose concrete is the 1-2-3 mix ratio.
1 Part: Portland Cement
2 Parts: Sand (Fine Aggregate)
3 Parts: Gravel / Crushed Stone (Coarse Aggregate)
This ratio is measured by volume, not by weight. For example, if you throw one 5-gallon bucket of cement into your mixer, you must add two 5-gallon buckets of sand and three 5-gallon buckets of gravel. This specific ratio yields approximately a 3,000 PSI concrete mix, which is perfect for sidewalks, patios, and residential foundations.
Concrete Mixing Ratio 1:2:4 (Alternative Mix)
In some older building codes or for specific non-structural applications, you will see a concrete mixing ratio 1:2:4.
This alternative recipe utilizes 1 part cement, 2 parts sand, and 4 parts gravel. By increasing the amount of cheap gravel and reducing the proportion of expensive cement paste, the mix becomes cheaper to produce. However, a 1:2:4 mix is harsher to trowel and finishes with a rougher surface. It is typically reserved for thick mass concrete pours, like massive trench footings, where a smooth surface finish is completely unnecessary.