About this tool Classify soil texture from the percentages of sand, silt, and clay using the USDA soil texture triangle. Enter the three fractions (must total 100%) and get the textural classification instantly.
The USDA texture triangle divides soils into 12 classes based on particle size distribution: Sand, Loamy Sand, Sandy Loam, Loam, Silt Loam, Silt, Sandy Clay Loam, Clay Loam, Silty Clay Loam, Sandy Clay, Silty Clay, and Clay.
Commonly used in agriculture, environmental science, and contaminated land assessment. For engineering classification, use the BS 5930 or USCS systems.
How to use this tool 1. Enter sand, silt, and clay percentages — from sieve analysis and hydrometer test results.
2. Ensure percentages total 100% — the tool shows a running total.
3. Read the classification — based on the USDA soil texture triangle.
Technical information USDA particle size boundaries: Sand 0.05–2.0 mm | Silt 0.002–0.05 mm | Clay < 0.002 mm
Note: BS/ISO uses different boundaries (sand 0.063–2.0 mm, silt 0.002–0.063 mm). If using BS sieve data, the classification may differ slightly from USDA.
Limitations The USDA texture triangle is an agricultural classification. It does not account for gravel content, plasticity, or organic content.
For geotechnical engineering purposes, use BS 5930 or USCS classification which incorporate Atterberg limits and engineering behaviour.
Revision history 9 June 2026: Initial release
Disclaimer This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.
Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.
All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.
By using this tool, you accept full responsibility for how you interpret and apply the information provided.
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