Add all ratio parts, divide each component by that total, and multiply the resulting share by the total mix volume.
Soil blend planning tool
Soil Mix Ratio Calculator
Split any total soil volume into topsoil, compost and an aeration component using custom ratios, percentages and optional local prices.
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Divide a soil blend by ratio
The calculator scales relative parts to the total volume.
Estimated result
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Enter the project details and calculate.
Ratio mechanism
Ratios describe shares of the total volume
A 6:3:1 blend has ten total parts. The calculator converts each component into a percentage and then applies it to the required volume.
Ratios can scale
6:3:1, 60:30:10 and 12:6:2 produce the same percentages. The relative relationship matters, not the size of the numbers.
Component volume = total volume × component parts ÷ total partsMaterial roles
Names such as topsoil and compost do not guarantee performance
Products vary widely in texture, maturity, salinity, contamination, nutrient content and drainage. The calculator should be paired with material specifications.
Topsoil
Provides mineral soil structure, but quality differs by source and screening.
Compost
Adds organic matter, yet immature or high-salt compost may create problems.
Aeration component
Sand, bark fines, perlite or other materials behave differently. Do not substitute by name alone.
Component costing
Price the blend before committing to a recipe
A small percentage of an expensive amendment can materially change the blend cost. Enter local unit prices to expose that trade-off.
The lowest-cost blend is not automatically the best agronomic blend. Cost is one constraint alongside drainage, water retention, crop needs and existing soil.
Frequently asked questions
Soil mix ratio calculator questions
No. Values such as 6:3:1 are automatically converted into 60%, 30% and 10%.
No. It is only an example. The correct blend depends on material quality, crop needs, drainage and existing soil.
Each component volume is converted into the selected pricing unit and multiplied by the local rate you enter.