Triangular Number Checker - Free, Instant, In Your Browser
Enter a positive whole number to check if it can be arranged as an equilateral triangle of dots (like 1, 3, 6, 10, 15...).
How to use Triangular Number Checker
- 1Paste your text or data into the input box above.
- 2Triangular Number Checker runs instantly, right in your browser.
- 3Copy the result or use it directly.
Your file is processed in your browser and is never uploaded.
Frequently Asked Questions
What's the formula?
The nth triangular number = n(n+1)/2. A number N is triangular if solving n(n+1)/2 = N for n gives a whole number.
Is my data sent to a server?
No - everything runs entirely in your browser with JavaScript. Nothing is uploaded.