Soil Mix Calculator is a powerful tool designed to help gardeners, landscapers, and soil specialists determine the ideal proportions of various soil amendments—specifically Topsoil, Compost, and Sand—to achieve a target soil texture based on USDA soil classification standards. Unlike general soil classification tools, this calculator goes a step further by estimating the exact volume and proportion of each material needed to fill a specified area with your desired soil quality.

Assumptions

This calculator assumes the following default compositions for the base materials:

• Topsoil: 60% sand, 25% silt, 15% clay
• Compost: 2% sand, 40% silt, 58% clay
• Sand: 95% sand, 4% silt, 1% clay

These typical values are derived from commonly available landscaping materials and may be adjusted based on local soil supply.

Inputs of Soil Mix Calculator

To use this tool, simply enter the length, width, and depth of the area you wish to fill. The units are flexible—you can choose between inches, feet, centimeters, or meters. In addition, select your target soil type from a dropdown menu based on USDA classification (e.g., Loam, Sandy Clay Loam, Silty Clay, etc.). Each type corresponds to a standard mix of sand, silt, and clay percentages.

Output of Soil Mix Calculator

The calculator will analyze your target soil composition and compute the most efficient mixing strategy using the available materials. You’ll receive both percentage ratios and actual volume requirements for each component. For example:

Target Soil: Loam
Total Volume (m³): 7.5
Recommended Mix:
■ Topsoil: 70.6% → 5.3 m³
■ Compost: 29.4% → 2.2 m³
■ Sand: 0.0% → 0.0 m³

This output ensures you can precisely prepare your planting area without guesswork, minimizing waste and improving plant performance.

Key Difference From Traditional Soil Type Classifiers

It’s important to note that this tool is not the same as a Soil Type Classification Calculator. While that tool takes existing percentages of sand, silt, and clay and identifies the soil class (e.g., Clay Loam, Sandy Loam), this Soil Mixer Calculator performs the inverse operation. It takes a desired soil class and calculates how to create that blend using real-world soil inputs.

This makes the tool invaluable for raised beds, greenhouses, lawn restoration, or any scenario where soil is being constructed or amended from scratch. By intelligently balancing materials, you can save cost, improve drainage, and optimize growing conditions.

Optimize Your Garden Soil

Whether you’re a hobby gardener or a professional landscaper, this soil blending calculator ensures you get the right balance of structure, fertility, and water retention in your soil. Get started today and grow with confidence.