USDA soil texture triangle
Representative horizons from five soil series.
USDA SSURGO via Soil Data AccessTernary Plot Maker
FigranMake a ternary plot from three-part compositions, or use the ternary diagram to classify soil samples.
- Paste or upload
- USDA soil classes
- SVG + 300 DPI PNG
Ternary plot examples: soil texture, AFM, phase and mixture diagrams
AFM diagram of Skye lavas
Alkalis, iron and magnesium for 23 lava samples.
MASS Skye, RdatasetsSimplex lattice mixture design: yarn elongation
Six mixture points colored by mean elongation.
NIST, Table 5.4Ternary phase diagram for liquid–liquid extraction
Experimental equilibrium of water, acetic acid and MIBK.
Laiadi et al. (2013), Tables I–IIDe Finetti diagram of genotype frequencies
Hardy–Weinberg curve and population points.
Hardy–Weinberg model · Illustrative valuesElectricity mix over time: United Kingdom
Annual generation by fossil, nuclear and renewable sources, 2000–2023.
Our World in Data / Ember · CC BY 4.0How to make a ternary plot
- Data
Clay, Sand, Silt 20, 40, 40 35, 30, 35
1Paste compositions
Paste or upload a table of three-part data.
2Map the components
Choose the three columns and optional groups or labels.
3Style and download
Adjust the ternary plot and export PNG, SVG or CSV.
How to read a ternary plot
- 1 Each point represents one composition.
- 2 Read the top component along a line parallel to the base.
- 3 Follow the other two grid directions to read the remaining components.
- 4 The three proportions add up to 100%. Clockwise and counterclockwise change the side on which each scale appears.
USDA soil texture triangle
The USDA triangle divides compositions into 12 texture classes. Sand particles are 2–0.05 mm, silt 0.05–0.002 mm, and clay less than 0.002 mm. The class at a sample's intersection describes its texture.
Marginal ranges; sloped boundaries determine each class.
| Class | Clay | Silt | Sand |
|---|---|---|---|
| Sand | 0–10% | 0–15% | 85–100% |
| Loamy sand | 0–15% | 0–30% | 70–90% |
| Sandy loam | 0–20% | 0–50% | 43–85% |
| Loam | 7–27% | 28–50% | 23–52% |
| Silt loam | 0–27% | 50–88% | 0–50% |
| Silt | 0–12% | 80–100% | 0–20% |
| Sandy clay loam | 20–35% | 0–28% | 45–80% |
| Clay loam | 27–40% | 15–53% | 20–45% |
| Silty clay loam | 27–40% | 40–73% | 0–20% |
| Sandy clay | 35–55% | 0–20% | 45–65% |
| Silty clay | 40–60% | 40–60% | 0–20% |
| Clay | 40–100% | 0–40% | 0–45% |
Source: Soil Survey Manual, chapter 3
Use the soil texture calculator to classify each row and count samples by class.
Ternary plot FAQ
How do you use the soil texture triangle?
Find the clay, sand and silt percentages along their grid lines. Their intersection gives the texture class; the table calculates it for each sample.
Can I make a ternary plot in Excel?
Excel has no native ternary chart. Copy three columns from your spreadsheet and paste them here to make a ternary plot.
Do my three values need to add up to 100?
No. Values are converted to proportions for plotting. Rows outside the closure tolerance are listed above the table.
Which way do the axes read?
Choose clockwise or counterclockwise for the ternary plot. Read each component along lines parallel to the edge opposite its vertex.
Can I color points by a fourth variable?
Yes. Map a numeric Value column to color the ternary plot with a continuous scale and color bar.
Can I draw phase boundaries or tie lines?
Use a Connect column to join rows with the same identifier in their original order.
Which soil classification does it use?
The overlay and calculator use the twelve USDA texture classes. Other classification systems are not included.
Is my data uploaded?
No. Your data and plot stay in your browser.
Make your ternary plot
Turn compositions into a figure ready to share.