Thematic Map Class Break Helper
A free, browser-based tool. Runs entirely in your browser — no sign up, nothing stored.
Values
Class breaks
Breaks: 3 → 12.25 → 21.50 → 30.75 → 40
| Class | Range | Count |
|---|---|---|
| 1 | 3 – 12.25 | 4 |
| 2 | 12.25 – 21.50 | 2 |
| 3 | 21.50 – 30.75 | 2 |
| 4 | 30.75 – 40 | 2 |
Equal interval splits the value range into equal-width classes; quantile puts roughly the same number of features in each class.
How to use this calculator
- Paste the values you're mapping (one per line or comma separated).
- Choose how many classes and the method — equal interval or quantile.
- Read the class break boundaries and how many features fall in each class.
How it works
Equal interval splits the value range into equal-width classes; quantile (equal count) puts roughly the same number of features in each class.
Use the counts to spot empty or lopsided classes before you finalise a choropleth map's legend.
Worked example
0–40 in 4 classes. Equal interval gives breaks 0, 10, 20, 30, 40; quantile would instead balance the count in each class.
Frequently asked questions
Which method should I pick?
Equal interval is easy to read on a legend; quantile shows variation when data is skewed. Try both and look at the per-class counts.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.