Enter sand, silt, and clay percentages to plot your sample and receive one of the 12 USDA texture classes immediately. This soil triangle calculator also supports rounded laboratory values and approximate jar-test measurements.
Jar test: Use the same unit for each settled mineral layer. Measure sand at the bottom, silt in the middle, and clay at the top; the calculator uses layer ÷ total mineral-layer thickness × 100.
Mix a representative, air-dried sample with water and a dispersing agent, remove roots and stones, shake thoroughly, then allow the layers to settle. Jar tests are approximate: organic matter, incomplete dispersion, settling time, and unclear boundaries reduce accuracy.
Totals within ±0.2 percentage points are accepted as rounding. Proportional normalization is limited to differences of 2 points or less and should not be used for missing or incomplete measurements.
Plotted at 40% sand, 40% silt, and 20% clay, in the Loam region.
Enter a valid composition to see the USDA class and typical management tendencies.
40% sand · 40% silt · 20% clay
The properties below are typical qualitative tendencies. Actual behavior also depends on structure, organic matter, density, profile depth, and site drainage.
USDA texture percentages describe the mineral fine-earth fraction less than 2 mm, generally by weight after appropriate sample preparation. USDA particle-size limits are sand 0.05–2.0 mm, silt 0.002–0.05 mm, and clay below 0.002 mm.
A valid composition totals 100%. Classification is determined by the exact regions and shared edges of a ternary diagram, not by selecting the largest fraction or applying one arithmetic formula. The implementation uses the 12 class boundary equations represented in the USDA NRCS Soil Survey Manual; there is no fallback label.
The calculator proportionally plots totals within ±0.2 percentage points to accommodate decimal rounding. The Normalize action rescales each fraction as fraction ÷ entered total × 100 and is intentionally limited to totals within 2 points of 100.
This is USDA agricultural soil texture. It is not the Unified Soil Classification System (USCS) or another engineering classification; those systems use different size limits and may require gradation and Atterberg-limit data.
Important limitations: Texture alone excludes coarse fragments, organic matter, aggregation and soil structure, compaction, salinity, restrictive layers, site drainage, and plasticity. These factors can make two soils in the same texture class behave differently.
The highlighted row follows the calculator result. All descriptions are typical tendencies rather than site-specific measurements.
| USDA class | Typical drainage | Water retention | Workability | Management considerations |
|---|---|---|---|---|
| Sand | Very rapid | Very low | Easy; dries quickly | Use small, frequent irrigation; reduce leaching and keep covered. |
| Loamy Sand | Rapid | Low | Generally easy | Use mulch and split water or nutrient applications. |
| Sandy Loam | Moderately rapid | Low to moderate | Usually easy | Watch surface drying and maintain organic inputs. |
| Loam | Moderate | Moderate | Generally favorable | Avoid wet traffic; schedule irrigation from actual root-zone conditions. |
| Silt Loam | Moderate to moderately slow | Moderate to high | Good at suitable moisture | Protect against crusting, sealing, and erosion. |
| Silt | Moderate to slow | High | Friable but fragile | Prioritize cover, aggregation, and low-intensity watering. |
| Sandy Clay Loam | Moderate | Moderate | Narrower moisture window | Avoid working wet soil and check infiltration. |
| Clay Loam | Moderately slow | High | Moisture-sensitive | Limit traffic when wet and preserve aggregation. |
| Silty Clay Loam | Slow to moderately slow | High | Difficult when wet or dry | Reduce compaction, crusting, and runoff risk. |
| Sandy Clay | Slow to moderate | High | Narrow moisture window | Avoid wet tillage and verify that irrigation infiltrates. |
| Silty Clay | Slow | High | Difficult | Use low irrigation rates and keep wet-soil traffic off. |
| Clay | Slow | High total; availability varies | Narrow moisture window | Irrigate slowly and protect aggregation. |
Arithmetic: 40% sand + 40% silt + 20% clay = 100%.
Plot and decision: The point sits inside the Loam polygon: clay is 7–<27%, silt is 28–<50%, and sand is ≤52%.
Interpretation: Typically moderate drainage and water storage with generally favorable workability.
82 + 12 + 6 = 100. Here silt + 1.5 × clay = 21 and silt + 2 × clay = 24, placing the point in Loamy Sand.
Expect rapid drainage, lower water storage, and greater leaching sensitivity.
20 + 65 + 15 = 100. Silt is at least 50% and clay is 12–<27%, so the point falls in Silt Loam.
Water retention is typically moderate to high, with crusting and erosion as key concerns.
20 + 20 + 60 = 100. Clay is at least 40%, sand is no more than 45%, and silt is below 40%.
The class typically has slow drainage, high retention, and a narrow workability window.
The entered total is 99.9%, only 0.1 point under. It is accepted within tolerance and plots proportionally; Normalize rescales it to 40.14%, 39.84%, and 20.02% before display rounding.
This Sandy Clay Loam point is only 0.1 point from the shared Loam vertex at 52% sand, 28% silt, and 20% clay. Ordinary measurement error could change the label.
A soil laboratory particle-size analysis is the most reliable source. A settled jar test can provide an approximate field estimate: measure each visible mineral layer and divide it by the total mineral-layer thickness.
First check transcription and whether all three fractions describe the same fine-earth sample. The calculator accepts totals within 0.2 percentage points as rounding and can proportionally normalize totals within 2 points. Do not normalize incomplete measurements.
They are Sand, Loamy Sand, Sandy Loam, Loam, Silt Loam, Silt, Sandy Clay Loam, Clay Loam, Silty Clay Loam, Sandy Clay, Silty Clay, and Clay.
No. Loam is often workable, but the best texture depends on the crop, climate, rooting depth, drainage, irrigation, and management. Structure and organic matter can matter as much as the class name.
Texture is the proportion of sand, silt, and clay in the fine-earth fraction. Structure is how particles bind into aggregates. Management can change structure much faster than it changes texture.
No. USDA texture uses the less-than-2-millimeter mineral fine-earth fraction. Remove coarse fragments from the basis, and do not enter organic matter as sand, silt, or clay.
It is an approximate screening method, not a substitute for laboratory particle-size analysis. Dispersion, organic matter, settling time, and unclear layer boundaries can all shift the result.
Texture classes share exact edges. A small measurement, sampling, or rounding change can move a point across an edge even when the soil itself has not meaningfully changed.
No. This calculator applies USDA agricultural texture classes. Geotechnical systems such as USCS use different particle-size limits and may require plasticity and gradation tests.
