Split a concrete or dry-mix quantity into cement, sand and coarse aggregate using the ratio you enter. Calculate by total dry volume, target wet concrete volume with an entered dry-volume factor, known cement quantity, or total dry weight. See material percentages, optional cement bags and optional material cost. Every numeric field uses a faint 0 placeholder only — the zero is not a real value.
The faint 0 inside each numeric field is only a placeholder. Type your number directly — typing 5 gives 5, not 05.
Your result appears after you press Calculate Proportions.
A ratio divides the same total into relative parts. For a 1:2:4 proportion, the mix contains 7 total parts: 1 part cement, 2 parts sand and 4 parts coarse aggregate.
Use the ratio you already have to divide a batch into cement, sand and coarse aggregate without pretending a generic ratio is a structural mix design.
See the cement share of the entered ratio and batch basis.
Calculate fine aggregate quantity from the same total parts.
Calculate coarse aggregate from the entered ratio.
See how much of the total each material represents.
Add optional unit costs for a simple material estimate.
Save the ratio and material breakdown for reference.
A concrete proportion is a relative relationship between materials. When a ratio is written as cement:sand:aggregate, each number represents parts on the same chosen basis. A 1:2:4 proportion contains 1 part cement, 2 parts sand and 4 parts coarse aggregate. The total is 7 parts, so cement represents 1/7 of the total, sand represents 2/7 and aggregate represents 4/7.
This calculator does not choose the ratio for you. That is intentional. Concrete performance depends on cementitious materials, aggregate grading, water content, admixtures, air content, workability, placement method, curing, exposure and required strength. The tool only divides quantities using the ratio you enter.
Total Parts = Cement Parts + Sand Parts + Aggregate PartsMaterial Quantity = Total Batch Basis × Material Parts ÷ Total PartsFor a 1:2:4 ratio, total parts equal 7. Cement is 14.29% of the total parts, sand is 28.57% and coarse aggregate is 57.14%. If the total dry mix volume is 70 ft³, the proportional quantities are 10 ft³ cement, 20 ft³ sand and 40 ft³ aggregate.
| Example Ratio | Total Parts | Cement Share | Sand Share | Aggregate Share |
|---|---|---|---|---|
| 1 : 1 : 2 | 4 | 25.00% | 25.00% | 50.00% |
| 1 : 1.5 : 3 | 5.5 | 18.18% | 27.27% | 54.55% |
| 1 : 2 : 3 | 6 | 16.67% | 33.33% | 50.00% |
| 1 : 2 : 4 | 7 | 14.29% | 28.57% | 57.14% |
| 1 : 3 : 6 | 10 | 10.00% | 30.00% | 60.00% |
These rows are arithmetic examples only. They do not recommend a structural concrete mix, strength class or project specification.
Use Dry Volume when you already know the total dry material volume you want to divide. Enter total cubic feet plus the cement, sand and aggregate parts. The calculator splits the total exactly by ratio.
Use Wet Volume when you start from a target finished concrete volume. Enter the target cubic yards and the dry-volume factor required by your estimating method. The calculator converts the target to cubic feet, multiplies by the entered factor and then divides that dry volume by the ratio parts.
If you already know how much cement you plan to use, select Cement Based. The entered cement volume represents the cement portion of the ratio. The calculator scales sand and aggregate proportionally. For example, if cement is 5 ft³ in a 1:2:4 ratio, sand is 10 ft³ and aggregate is 20 ft³.
Weight mode divides a total dry weight according to the ratio parts. If the ratio is defined by weight, this gives each material in pounds. Do not mix volume-based ratios and weight-based ratios unless your specification explicitly tells you how to convert between them.
A ratio only makes sense when its basis is clear. One cubic foot of cement does not weigh the same as one cubic foot of sand or coarse aggregate. If a mix specification is written by mass, use weight mode. If it is a site-batching volume proportion, use a volume mode.
The optional bag calculation needs the volume represented by one cement bag. Enter that value in cubic feet per bag. The calculator divides cement volume by the bag volume and rounds up to whole bags. If the bag-volume field is blank, the calculator does not invent a bag count.
You can optionally enter cement price per bag plus sand and aggregate cost per cubic foot. The cost result is a basic material estimate only. It excludes water, admixtures, delivery, labour, equipment, mixing, pumping, placement, testing and curing.
Water demand is not another simple part of a cement:sand:aggregate ratio. Water-cement ratio, aggregate moisture, absorption, workability, admixtures and required performance all matter. Automatically guessing water from a nominal ratio could create a misleading mix-design result, so this calculator does not do it.
Proportion arithmetic tells you how to divide a total. Concrete mix design determines whether a combination of materials can meet strength, durability, workability, density and placement requirements. That usually requires material properties, trial batches, specification limits and qualified technical judgment.
This Concrete Proportion Calculator performs ratio arithmetic only. It does not determine water-cement ratio, compressive strength, slump, air content, cement type, aggregate grading, admixture dosage, durability exposure, pumpability or compliance with a concrete specification.
For related estimating, use the Cement Sand Gravel Calculator, Concrete Batch Calculator, Concrete Volume Calculator and Concrete Ready Mix Calculator.
A ratio can split materials accurately while still saying nothing about whether the concrete will meet the required performance.
Ratio parts divide the selected batch basis.
Water demand must come from the mix design, not a guessed ratio.
Strength and workability depend on more than three dry-material parts.
Use approved specifications and qualified guidance for final batching.
Answers about ratio parts, dry volume, weight basis, cement bags and mix-design limits.
It splits a target concrete or dry-mix quantity into cement, sand and coarse aggregate from the ratio parts you enter.
The 0 is only a placeholder, not a real value. Typing 5 gives 5 rather than 05.
It contains 1 part cement, 2 parts sand and 4 parts coarse aggregate on the same chosen basis, for 7 total parts.
Yes. Enter any positive ratio appropriate for your project or specification.
Yes. Use Wet Volume and enter the target finished volume plus your dry-volume factor.
It is an estimating multiplier applied to finished concrete volume. The calculator requires you to enter it rather than forcing one assumption.
Yes. Use Weight Ratio and enter total dry weight plus the ratio parts.
No. It only divides quantities using the ratio you enter.
No. Water demand and water-cement ratio are separate mix-design decisions.
Yes. Enter the volume represented by one cement bag.
Yes. Enter optional cement, sand and aggregate unit costs.
Yes. The PDF includes the ratio, material quantities, percentages, bag estimate and cost.
Use approved project specifications and authoritative concrete resources alongside any ratio arithmetic.
Concrete standards, education and technical resources.
Visit ACIReady-mixed concrete technical and educational resources.
Visit NRMCAConcrete and cement education covering mixture ingredients and construction.
Visit PCASafety information about respirable crystalline silica associated with concrete materials and work.
Read OSHA Guidance