Find the area of a triangle two ways: from its three side lengths using Heron formula, or from a base and its height using the classic half base times height. Heron formula is especially useful when you know the three sides but not the height, which is the common case for a plot of land or an irregular shape; it first computes the semi-perimeter, then takes a square root of a product of differences. This calculator also validates that the three sides can actually form a triangle, so it warns you if they violate the triangle inequality instead of returning a meaningless number. The base and height method is there for the simpler case. Enter your measurements and the area appears instantly. Everything is computed locally in your browser, so it is fast and private.
Heron formula finds a triangle area from its three sides using the semi perimeter, without needing a height.
Yes. If you know the base and the perpendicular height, the tool uses half of base times height.
If any side is longer than the sum of the other two the sides do not close into a triangle and no valid area exists.
Find the area of a triangle two ways: from its three side lengths using Heron formula, or from a base and its height using the classic half base times height. Heron formula is especially useful when you know the three sides but not the height, which is the common case for a plot of land or an irregular shape; it first computes the semi-perimeter, then takes a square root of a product of differences.
Yes. Triangle Area Calculator (Heron Formula) is completely free, with no sign-up and no usage limits.
Yes. Triangle Area Calculator (Heron Formula) runs in any modern web browser. There is nothing to download or install.
Yes. Triangle Area Calculator (Heron Formula) runs entirely on your device in your browser, so nothing you enter is uploaded to a server.