Triangle Inequality Calculator

Check whether three side lengths can form a triangle.

Last updated: June 2026 | By Patchworkr Team

Triangle Validity Check

Math check: a + b > c, a + c > b, and b + c > a

Result

Enter three positive side lengths to test validity.

Inequalities

Enter all three sides to see the checks.

For sides 5, 7, and 11, the checks are 5 + 7 = 12 > 11, 5 + 11 = 16 > 7, and 7 + 11 = 18 > 5.

Because all three are true, the side lengths form a valid triangle.

A triangle is valid only if each pairwise sum is strictly greater than the remaining side.

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