Math Calculators

Geometry and everyday math

These tools handle the geometry and arithmetic that come up in study, making, and design — the kind of problem where you know some of the measurements and need the rest. Each one shows the method it uses, not just the answer, so it doubles as a way to check your own working.

The triangle solver takes any three measurements of a triangle and finds everything else with the law of sines and cosines. The right triangle calculator is the specialised version for a 90° corner — enter any two values and it uses the Pythagorean theorem and trig — and thecircle calculator converts between a circle's radius, diameter, circumference, and area. Thetrigonometry calculator gives the sine, cosine, tangent, and their reciprocals for any angle — or works backwards from a ratio to an angle. More geometry and math tools will join this category over time.

What the solvers actually do

These are working tools rather than teaching aids, but each shows its method alongside the answer so you can follow it or check it by hand. The triangle solver picks between the law of sines and the law of cosines depending on which three values you supply, and warns about the ambiguous case — where two sides and a non-included angle describe two genuinely different triangles. The quadratic solver reports the discriminant, so you can see immediately whether the roots are real, repeated or complex rather than just receiving a result.

Exactness and floating point

Where a result can be exact, these tools keep it exact. The fraction calculator works in integers and reduces by the greatest common divisor, so a third plus a sixth returns exactly one half rather than 0.49999999999999994. GCD and LCM are integer arithmetic throughout.

Where a result cannot be exact — anything involving a square root, a trigonometric function, or π — the answer is a floating-point approximation, rounded for display rather than truncated. If you need a value to feed into further work, use the full precision shown rather than retyping a rounded figure, because rounding early is how small errors compound into visible ones.

Degrees, radians, and the usual mistake

The most common wrong answer in trigonometry is a unit error rather than a method error. Every page here that takes an angle states its unit and lets you choose, and the angle converter moves between degrees, radians and gradians. If a trigonometric result looks wildly wrong, check the unit before checking anything else — it is nearly always that.