Triangle Calculator
Three sides are enough — Heron’s formula gives the area without needing a height.
Why Heron matters
Most area formulas need a height. With only three sides, Heron gives the area directly — useful on site, where measuring a height is often impossible.
Triangle inequality
Any two sides must add to more than the third. If they do not, the shape cannot close — the calculator says so instead of returning a nonsense area.
What is a 3-4-5 triangle?
A right triangle — the simplest Pythagorean triple, used for squaring corners on site.
Does it handle decimal sides?
Yes, and it checks the inequality with tolerance.