Isosceles Triangle Calculator
Calculate the area, height, and perimeter of an isosceles triangle from its equal sides and base.
- Height
- 4
- Perimeter
- 16
Formula: A = (b/4) × √(4a² − b²)
About Isosceles Triangle Calculator
Isosceles Triangle Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate the area, height, and perimeter of an isosceles triangle from its equal sides and base.
The calculation uses the standard formula A = (b/4) × √(4a² − b²) and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.
The height from the apex of an isosceles triangle always bisects the base, splitting it into two congruent right triangles.
Frequently Asked Questions
Is Isosceles Triangle Calculator free to use?
Yes. Isosceles Triangle Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.
How accurate is this calculator?
The calculator applies the standard formula (A = (b/4) × √(4a² − b²)) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.
Why do I get no result for some inputs?
The two equal legs must together be longer than the base (2a > b), otherwise the sides cannot close into a triangle.
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