Mixing concrete yourself? Enter the volume and choose a mix ratio such as 1:2:3, 1:2:4 (M15) or 1:1.5:3 (M20) to get how many bags of cement you need and how much sand, gravel and water to add, in kilograms, pounds and cubic units.
Last updated:
0.45–0.55 is typical; less water = stronger
Standard 1.54 (bulking and voids)
%
Enter your values to see the result.
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How to use the Concrete Mix Ratio Calculator
Enter the volume of concrete and its unit (work it out with the concrete volume calculator if needed).
Choose the mix ratio by grade (M20, M15…) or a custom cement : sand : gravel ratio.
Select your cement bag size and adjust the water-cement ratio and waste if you like.
Read the cement bags, sand, gravel and water and download the materials list.
The dry volume method
Dry volume = wet volume × 1.54 × (1 + waste %)
Each material's volume = dry volume × its part ÷ sum of parts
Example: 1 m³ of M20 (1:1.5:3): dry volume 1.54 m³, sum of parts 5.5. Cement = 1.54 ÷ 5.5 = 0.28 m³ × 1,440 = 403 kg (8.1 bags of 50 kg); sand = 0.42 m³ (672 kg); gravel = 0.84 m³ (1,260 kg); water at 0.5 = 202 L.
Materials per cubic meter (no waste)
Grade / ratio
Cement
50 kg bags
Sand
Gravel
M25 · 1:1:2
554 kg
11.1
0.385 m³
0.77 m³
M20 · 1:1.5:3
403 kg
8.1
0.42 m³
0.84 m³
1:2:3
370 kg
7.4
0.513 m³
0.77 m³
M15 · 1:2:4
317 kg
6.3
0.44 m³
0.88 m³
M10 · 1:3:6
222 kg
4.4
0.462 m³
0.924 m³
M7.5 · 1:4:8
171 kg
3.4
0.474 m³
0.948 m³
For structural work such as footings and columns, follow your engineer's mix design or use ready-mix or bagged concrete with a stated strength. Mix ratios by volume are best for small, non-critical pours.
Frequently asked questions
How do you calculate cement, sand and gravel for concrete?
Multiply the wet volume by about 1.54 to get the dry volume of materials (they shrink when water fills the gaps). Split that dry volume by the mix ratio: for 1:2:4 the cement is 1/7, sand 2/7 and gravel 4/7. Multiply the cement volume by 1,440 kg/m³ and divide by the bag weight to get bags.
How many bags of cement are in 1 cubic meter of concrete?
With the dry volume method, 1 m³ of 1:1.5:3 (M20) concrete needs about 403 kg of cement, or roughly 8.1 bags of 50 kg. A 1:2:4 (M15) mix needs about 317 kg (6.3 bags) and 1:3:6 (M10) about 222 kg (4.4 bags), before waste.
What is the ratio for M15, M20 and M25 concrete?
In nominal mix design (as used in Indian Standard IS 456), M10 is 1:3:6, M15 is 1:2:4, M20 is 1:1.5:3 and M25 is 1:1:2 cement : sand : coarse aggregate by volume. The number is the target compressive strength in N/mm² (MPa) after 28 days. Higher grades should use a designed mix.
Why multiply by 1.54?
Dry cement, sand and gravel contain air gaps. When water is added, the fine particles fill those voids and the mix loses volume, so you need about 52–57% more dry material than the finished volume. 1.54 is the standard factor; some use 1.52 to 1.57.
How much water should I add?
Water is set by the water-cement ratio: 0.5 means 0.5 liters of water per kilogram of cement, or about 25 liters per 50 kg bag. Less water makes stronger, more durable concrete; add only enough for a workable mix, and account for wet sand.
What density values are used?
Cement 1,440 kg/m³, dry loose sand 1,600 kg/m³ and gravel 1,500 kg/m³. Real densities vary with moisture and grading, so buy a little extra sand and gravel.
Is my data sent anywhere?
No. Everything is calculated in your browser.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.