Soil Texture Triangle Classifier: USDA Sand, Silt, and Clay Calculator

Enter your sand, silt, and clay percentages to instantly identify your USDA soil texture class, visualize your composition on the ternary triangle, and read agronomy telemetry including drainage rate, water holding capacity, and nutrient retention.

Panel 1: Soil Composition Input
Sand
%
Silt
%
Clay
%
Total: 100%
Lock and Balance
Panel 2: USDA Soil Texture Triangle Visualizer
Sand % Clay % Silt % 100% 100% 100%
USDA Soil Texture Classification System - 12 Texture Classes
Panel 3: Agronomy Telemetry
Soil Texture Classification
Loam
USDA Texture Class
Sand 42%
Silt 40%
Clay 18%
Drainage Rate Moderate
Water Holding Capacity High
Nutrient Retention High
Permeability Moderate
Workability Good
Compaction Risk Low-Moderate
Key Terms Explained: Soil Science Glossary
Soil Texture
The relative proportion of sand, silt, and clay particles in a soil sample. Texture is a permanent, intrinsic soil property that directly controls drainage, aeration, and nutrient storage.
Loam
A balanced soil texture class containing moderate proportions of sand, silt, and clay (roughly 23-52% sand, 28-50% silt, 7-27% clay). Loam is widely considered the most fertile and productive agricultural soil type.
Ternary Graph
A triangular diagram used to visualize three components that must sum to 100%. In soil science, the three axes represent sand, silt, and clay percentages. Each point inside the triangle corresponds to one unique soil composition.
Water Holding Capacity
The maximum amount of plant-available water a soil can retain against gravity after free drainage has ceased (field capacity minus permanent wilting point). Clay-rich soils hold more water; sandy soils drain quickly and hold less.
Particle Size
The physical diameter of individual soil mineral particles. USDA classifications: Sand (2.0 to 0.05 mm), Silt (0.05 to 0.002 mm), Clay (less than 0.002 mm). Particle size is the primary determinant of soil texture class.
Permeability
The rate at which water moves through a soil profile. High-permeability (sandy) soils drain rapidly; low-permeability (clay) soils drain slowly. Permeability affects irrigation scheduling, runoff risk, and root zone aeration.
Ribbon Test
A field method for estimating clay content. Moisten a soil sample and press it between thumb and forefinger to form a ribbon. Soils that form long, smooth ribbons (5+ cm) are high in clay; soils that crumble have low clay content.
Cation Exchange Capacity (CEC)
A measure of a soil's ability to hold and exchange positively charged nutrient ions (cations) such as calcium, magnesium, and potassium. Clay particles and organic matter have high CEC, making nutrient retention strongly correlated with clay content.

The Complete Guide to USDA Soil Texture Classification

If you are trying to understand your soil for gardening, farming, construction, or land management, the first step is identifying its texture class. Soil texture determines how your ground holds water, drains after rain, stores nutrients for plant roots, and responds to tilling or compaction. The USDA Natural Resources Conservation Service (NRCS) uses a 12-class system based on the relative percentages of sand, silt, and clay - the three fundamental mineral particle size fractions found in virtually every soil on Earth.

How to Use This Soil Texture Triangle Calculator

Adjust the Sand, Silt, and Clay sliders in Panel 1 until they reflect your soil composition. The tool enforces a 100% total at all times using the Lock and Balance feature. As you move the sliders, the ternary triangle in Panel 2 updates in real time, plotting a glowing crosshair precisely on the correct zone of the USDA texture triangle. Panel 3 displays the classified texture name and six derived agronomic characteristics, updated instantly with every slider movement. No form submission is needed.

If you do not yet know your soil percentages, the mason jar test described in the FAQ below provides a reliable at-home estimate. For precise results, send a sample to your local cooperative extension service for a standard mechanical analysis (hydrometer method or laser diffraction).

The 12 USDA Soil Texture Classes Explained

The USDA recognizes 12 texture classes: Sand, Loamy Sand, Sandy Loam, Loam, Silt Loam, Silt, Sandy Clay Loam, Clay Loam, Silty Clay Loam, Sandy Clay, Silty Clay, and Clay. The boundaries between classes are defined by specific percentage thresholds that form the characteristic polygon zones on the texture triangle. A soil is classified as Loam, for example, only if sand falls between 23 and 52 percent, clay between 7 and 27 percent, and silt is at least 28 percent but not over 50 percent.

Sandy soils (Sand, Loamy Sand) have the largest particles and the fastest drainage, making them suitable for root vegetables and drought-tolerant crops but prone to nutrient leaching. Clay soils (Clay, Silty Clay, Sandy Clay) have the smallest particles, the highest water and nutrient retention, and the slowest drainage, which can cause waterlogging and poor aeration. The Loam family of classes sits at the productive center of the triangle, balancing all three particle types.

Why Soil Texture Matters for Plants and Agriculture

Texture controls nearly every physical property that matters to plant growth. Drainage rate determines whether roots can access oxygen after rainfall. Water holding capacity determines how long plants can survive between irrigation events. Nutrient retention determines fertilizer efficiency - nutrients applied to sandy soil may leach out before roots can absorb them. Workability determines when you can till or plant without damaging soil structure. Understanding your texture class is therefore the foundation of any crop management, irrigation design, or land drainage plan.

Agronomy Characteristics by Texture Class

The telemetry values shown in Panel 3 are derived from published USDA NRCS data and standard agronomic literature. Drainage rate ranges from Very Slow (heavy clay) to Very Rapid (coarse sand). Water holding capacity ranges from Very Low (sand) to High (clay loam and loam). Nutrient retention follows a similar pattern, peaking in clay-dominant and loam classes where cation exchange capacity is highest. Permeability, workability, and compaction risk are also texture-dependent and are provided as qualitative descriptions to guide practical decisions in the field or garden.

Frequently Asked Questions: Soil Texture and Classification

The USDA particle size classification defines sand as particles ranging from 0.05 to 2.0 millimeters in diameter. Silt particles are much smaller, ranging from 0.002 to 0.05 millimeters. Clay particles are the finest of all, measuring less than 0.002 millimeters (2 micrometers) in diameter. To put this in perspective, a single grain of coarse sand can be roughly 100 times wider than a clay particle. This size difference is the primary driver behind all differences in drainage, water holding capacity, and nutrient retention between the three particle types.
Loam (roughly 23-52% sand, 28-50% silt, and 7-27% clay) is considered ideal because it balances the competing properties of all three particle sizes. Sand provides the large pore spaces needed for adequate aeration and drainage, preventing waterlogged root zones. Silt contributes moderate water retention and a workable, friable texture. Clay supplies the cation exchange capacity that holds plant nutrients like calcium, magnesium, and potassium against leaching. Loam also warms quickly in spring, drains well enough to avoid root rot, yet retains enough moisture to buffer against short dry spells - making it highly productive for vegetables, grains, and most garden crops.
Clay particles are plate-shaped with an enormous surface area relative to their volume. This causes clay-rich soils to hold large amounts of water through surface adhesion and to pack tightly, dramatically reducing the size of pore channels that allow water to drain through. Soils with more than 40% clay (classified as Clay in the USDA system) can drain as slowly as 0.05 centimeters per hour compared to 2.5 centimeters per hour or more for sandy loam. Clay also swells when wet and shrinks when dry, creating cracks that can bypass the matrix. High clay content is beneficial for water storage in dry climates but problematic for root aeration in wet conditions.
Organic matter does not change the fundamental particle size distribution of your soil - the sand, silt, and clay percentages remain the same after adding compost. What changes is the soil structure: organic matter binds particles into aggregates called peds or crumbs, which create larger and more stable pore networks. In clay soils, this aggregation improves drainage and aeration. In sandy soils, organic matter fills gaps between large particles, improving water and nutrient retention. These structural improvements are significant and long-lasting, but they are a function of soil biology and aggregate stability, not a change in texture class.
Fill a quart-sized jar one-third full with dry soil, removing any roots or debris. Add water until the jar is nearly full, then add one teaspoon of dish soap or water softener salt. Shake vigorously for at least 3 minutes, then let the jar sit undisturbed for 48 hours. Sand settles first within 1-2 minutes, forming the bottom layer. Silt settles next within 1-2 hours, forming the middle layer. Clay remains suspended longest and settles last over 24-48 hours, forming the top layer above the silt. Measure the total settled depth and each layer's depth, then calculate each as a percentage of the total. Enter those values into this calculator to identify your USDA soil texture class.