Ternary Diagram Maker (Free, Online)
A clean, blank three-component triangle for any compositional data. Label the apices yourself, paste your numbers, and export a vector figure.
What a ternary diagram shows
A ternary diagram plots three components that sum to a constant — normally 100%. Because the third value is fixed once the other two are known, three proportions can be shown on a flat triangle with no information lost. Every point inside the triangle is one unique composition; each apex is 100% of that component and the side opposite an apex is 0% of it.
Geology reaches for them constantly, because so much of what we measure is a proportion of a whole: QAPF for igneous rocks, sand–silt–clay for sediments, Q–F–L for sandstone provenance, AFM for magmatic differentiation trends, and major-ion ratios in water chemistry.
Data
Paste straight from Excel or Google Sheets — include the header row and the columns are matched by name, in any order.
| # | A% | B% | C% | Label(opt) | Group(opt) | |
|---|---|---|---|---|---|---|
| 1 | ||||||
| 2 | ||||||
| 3 | ||||||
| 4 |
0 rows of data
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Enter data on the left to plot it
SVG is vector — resize it in Illustrator or Inkscape without losing quality. PNG 4× is roughly 600 dpi at figure width.
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How to read it
Pick an apex. The proportion of that component is read along lines drawn parallel to the side opposite it, increasing towards the apex. Beginners usually go wrong by reading along the wrong axis direction; the reliable check is that a point sitting on the base line must contain zero of the top component.
Rows are normalised for you, so raw counts, grams or percentages that do not quite total 100 will still plot correctly. What normalisation cannot fix is the deeper issue: compositional data are closed. Because the parts must sum to a constant, increasing one component mechanically decreases the others, which can manufacture correlations that mean nothing. Treat apparent trends in a ternary as a description, not as evidence of a process, unless you have tested them properly.
Common questions
- Do my three values have to add up to 100?
- No. Each row is normalised to its own total, so counts, weights or percentages all work. A row of 62, 21, 17 and a row of 620, 210, 170 plot in the same place.
- Can I add field boundaries?
- The preset diagrams (USDA soil texture, QFL provenance) come with their published fields drawn in. The blank ternary is deliberately empty for compositions that have no standard classification.