Is this Law of Cosines Calculator free to use?

Yes, Law of Cosines Calculator is 100% free to use online with no installation or account required.

How do I use the Law of Cosines Calculator?

Simply enter your values into the required input fields and click calculate to view the results instantly.

Yes, the calculator is fully responsive and compatible with Android, iOS, Windows, macOS, and Linux web browsers.

Law of Cosines Calculator — Free Online Tool

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Find third side: c² = a² + b² − 2ab cos C

Note: Generalizes Pythagorean theorem for any triangle.

Sides and angle

Side a

Side b

Angle C (°)

⚠️ For educational purposes only. Verify results with a qualified professional when making important decisions.