Area of an equilateral triangle
Area of an equilateral triangle: enter the dimensions to calculate the result in the correct units.
Enter your values, then calculate.
Your calculation stays in your browser.
The formula, explained
sqrt(3)*s^2/4s : SideAn example to check
Using the starting values below, the calculation gives:
The surface to measure or cover — The calculated area is 15.5885 cm², equivalent to 0.00155885 m². It measures a surface, not the length around it.
When buying a covering, distinguish theoretical area from order quantity: cuts, joints and pack sizes can affect what you need.
How to use this tool
Check the required inputs: side.
Choose the units and options that match your task. Calculate, check the result and use Copy or Print to keep a record. Rounding applies to the display; keep more precision in intermediate steps.
Can I use a decimal comma?
Yes. Numeric fields accept 12.5 or 12,5 and spaces for thousands, such as 1 234.50. Do not mix a point and comma in one number.
Where are my inputs processed?
Calculations run in your browser. Form values are not sent to Analytics. Copying, printing, sharing or opening an external service is your choice.
Method and interface checked on 2026-09-19 · Report an error