How do I measure sand, silt, and clay percentages?

The standard laboratory method is hydrometer analysis (ASTM D422) or pipette method, which separates particles by settling velocity in water. Field estimates can be made using the ribbon, ball, and jar sedimentation tests, but laboratory analysis gives accurate percentages for correct USDA classification.

Why do my percentages not add up to 100%?

In USDA particle-size analysis, sand + silt + clay must equal 100% (organic matter, gravel, and coarse fragments are excluded before the analysis). If your lab report includes other fractions, remove them and re-normalize to the fine-earth fraction only.

What is the difference between Sandy Loam and Loamy Sand?

Both are coarse-textured soils, but loamy sand has a higher sand content (typically 70–90%) and behaves almost like pure sand. Sandy loam has enough silt and clay to hold its shape briefly when moist and supports more plant growth and water retention than loamy sand.

How does soil texture affect plant growth?

Texture controls water retention, drainage, aeration, and nutrient-holding capacity (CEC). Sandy soils drain fast and have low CEC; clay soils retain water and nutrients but can become waterlogged and hard to till. Loam textures balance these properties and are considered optimal for most crops.

Can I change soil texture?

Texture is difficult to change permanently since it requires adding very large volumes of sand or clay. Adding organic matter does not change texture classification but dramatically improves soil structure, water retention in sandy soils, and drainage in clay soils — the practical alternative to texture modification.

Soil Texture Calculator

Name: Soil Texture Calculator
Availability: InStock
Author: Nham Vu

Enter the percentages of sand, silt, and clay in your soil sample to get the USDA texture class and see your sample plotted on the soil texture triangle.

Particle Size Fractions

Sand (%) — 2.0 to 0.05 mm

Silt (%) — 0.05 to 0.002 mm

Clay (%) — less than 0.002 mm

Sum: — / 100%

Quick Presets

Enter sand, silt, and clay percentages, then click Classify to see your USDA soil texture class.

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Summary

Enter the percentages of sand, silt, and clay in your soil sample to get the USDA texture class and see your sample plotted on the soil texture triangle.

How it works

Enter the percentage of sand in your soil sample (0–100).
Enter the percentage of silt in your soil sample (0–100).
Enter the percentage of clay in your soil sample (0–100).
Verify the three values sum to exactly 100% — an error is shown if they do not.
Click Classify to see the USDA texture class and view your sample on the texture triangle.

Use cases

Determine irrigation requirements — sandy soils drain quickly; clay soils retain water.
Select appropriate tillage equipment and timing based on soil workability.
Match crop types to soil suitability: loam soils suit most crops; heavy clays suit rice.
Estimate soil water-holding capacity and aeration for drainage system design.
Interpret soil test reports and laboratory particle-size analysis results.
Identify compaction risk — silty clay loams and clay loams compact under machinery.
Plan compost and organic matter amendments to improve texture class over time.
Assess septic system suitability based on percolation characteristics.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu