Hydrochart is a free, browser-based Piper diagram maker. Load your major-ion analyses, and it plots the trilinear cation and anion triangles and the central diamond, classifies each sample's water type, and flags any analysis whose charge balance is off. Everything runs locally — your data never leaves your device.
Make a Piper diagram in three steps
Load your data
Open the plotter and drop in a CSV or Excel file of major-ion concentrations, or paste a table. Column headers are matched automatically.
Get the diagram
Hydrochart draws the Piper diagram instantly and colours each point by water type. A charge-balance error is computed and flagged beyond ±5%.
Export it
Download the finished diagram as vector SVG or PNG — sharp at any size, ready for a report, thesis or paper.
What data do I need?
A Piper diagram is built from the major ions. Supply them in mg/L and Hydrochart converts to milliequivalents and computes the percentages for you:
| Group | Ions |
|---|---|
| Cations | Calcium (Ca), Magnesium (Mg), Sodium (Na), Potassium (K) |
| Anions | Bicarbonate (HCO₃) and Carbonate (CO₃), Sulfate (SO₄), Chloride (Cl) |
| Optional | TDS, pH and EC — used for labelling and QA, estimated when absent |
Not sure of the layout? Download the CSV template and paste your values into it.
Why use Hydrochart
- Genuinely free. Create and view unlimited Piper diagrams with no account. Free exports carry a small watermark; Pro (USD $29/year) removes it and adds CSV export.
- Nothing is uploaded. The whole tool runs client-side in your browser, so confidential monitoring data stays on your machine.
- Publication-ready output. Vector SVG and PNG export, with drag-to-place sample labels and leader lines for clean figures.
- More than Piper. The same dataset also plots Stiff, Schoeller, Chadha, Durov and Gibbs diagrams — no re-entry.
- Built-in quality control. Every analysis gets a cation–anion charge-balance error, flagged when it exceeds ±5%.
New to Piper diagrams?
If you want to understand what the triangles and the diamond actually mean before you plot, read the companion guide: how to read a Piper diagram. It walks through the axes, the water-type regions, and how to interpret where your samples fall.