Triangle Area Calculator
Solve any triangle from three known values — SSS, SAS, ASA, AAS or SSA — and get every side, every angle, the area, the perimeter and the heights, with the law of sines and cosines steps written out and a scaled diagram.
Result
This page opens the triangle calculator with the area as the headline result. Enter three sides and the area comes from Heron's formula — s = (a + b + c)/2, then √(s(s−a)(s−b)(s−c)) — or switch to a case with a known angle and the calculator uses ½·a·b·sin C instead. Either way the formula and the substituted numbers are printed as explicit steps.
The default 3-4-5 example gives an area of exactly 6: the semi-perimeter is 6, and √(6·3·2·1) = √36 = 6. Because 3-4-5 is a right triangle, the same number also falls out of the shortcut ½·3·4 — a handy way to see that both methods agree before you trust the tool with messier sides.
Alongside the area you still get the full solution: every angle, the perimeter and the three heights, which follow directly from the area as h = 2·Area/side. That makes this page useful for land-plot estimates, fabric and material cutting, geometry homework and any task where the area is the number you actually came for.