Math calculators

Every category on this site uses math, but those tools are built for a specific domain — a mortgage calculator knows about amortization schedules, a BMI calculator knows about WHO thresholds. This category is different: it covers the general-purpose math that doesn't belong to any single domain. Students checking homework, writers verifying a proportion, analysts doing a quick statistical sanity check, engineers confirming a formula before they reach for something heavier — this is where that work happens.

The basic subcategory covers arithmetic building blocks that come up constantly. The percentage calculator handles four operations in one tool: find a percentage of a number, find what percentage one number is of another, find the original value before a percentage change, and find the percentage difference between two values. Fraction and ratio calculators join it, along with proportion solving and exponent computation — including fractional exponents (cube roots, fourth roots) that most phone calculators handle awkwardly.

The statistics subcategory covers the core descriptive and inferential measures. A standard deviation calculator (showing both population and sample formulas), a mean/median/mode calculator that handles datasets pasted in as comma-separated values, a z-score calculator for standardizing values against a known mean and standard deviation, and a permutations and combinations calculator for counting problems. These are the statistics most people need when they need statistics — not a replacement for R or Python, but fast enough for the moment you need to check a number.

The geometry subcategory handles shapes and spatial relationships: triangle solving (Pythagorean theorem, law of cosines, area from three sides via Heron's formula), area for common shapes, circle properties from any single input (radius gives you diameter, circumference, and area simultaneously), and the distance-between-points formula for two coordinate pairs.

The algebra subcategory covers equation solving: quadratic equations (showing both real and complex roots where they exist), linear equations, systems of two equations in two unknowns, and logarithm evaluation in any base. A scientific calculator rounds out the set for cases where you just want to evaluate an expression.

What these tools are not: a graphing calculator, a computer algebra system, or a proof assistant. They don't plot functions, don't simplify symbolic expressions, and don't produce step-by-step derivations. For those tasks, Wolfram Alpha, GeoGebra, or Desmos are the right tools. These pages are for the numerical case — you know what formula applies and you want the answer for your specific inputs, shown clearly with the formula documented so you can verify the result yourself.