Triangle Angles Calculator
Find a triangle’s angles from its sides.
Result
How to use
- Enter your values in the fields above.
- Press Calculate to see your result instantly.
- Use the Share button to copy a link to your result.
About this calculator
Given the three side lengths of a triangle, this calculator finds all three angles using the law of cosines, cos(A) = (b² + c² − a²) / (2bc), applied once per angle and then checked so the three sum to 180°.
It's used by surveyors and carpenters framing angled cuts like roof trusses or staircases where only the side lengths are easy to measure directly, and by students working through trigonometry problems that go beyond the simpler right-triangle cases.
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