Solve f(x)

Every root, real and complex, in one tap. Quadratics, cubics, quartics and beyond instantly, offline, no account needed.

Most calculator apps stop at quadratics. Solve f(x) doesn't.

Solve f(x) solves polynomials of any degree, from simple linear equations up through degree 20, and finds every root, real and complex, instantly and entirely offline. No account, no internet connection, no data collected.

Free: degrees 1–3, real roots, interactive graph, dark mode. PolySolve Pro ($5, one-time): degree 4 through 20, complex roots, multiplicity detection, higher precision, and solve history.

FEATURES • Solve any polynomial, degree 1 through 20 • Every root: real and complex, with multiplicity detection (e.g. (x-2)² correctly shows a repeated root) • Exact symbolic answers for degree 1 and 2 when they simplify cleanly (e.g. x = (-1 + √5)/2), plus decimal values everywhere • Two ways to enter a polynomial: a simple coefficient list, or type it naturally like "3x^4 - 2x^2 + 7x - 1" • Interactive graph with pinch to zoom and pan, real roots marked directly on the curve • Solve history so you can revisit anything you've worked on • Adjustable precision 4, 8, or 12 decimal places • Full dark mode support

Built for engineering and math students who hit a wall the moment a problem goes past a quadratic and for anyone who just wants correct answers fast, without ads or a subscription.

Solve f(x) Pro is a one-time purchase that unlocks degree 4 and higher, complex roots, multiplicity detection, extended precision, and solve history. No subscriptions, ever.