Quadratic Equation Solver Calculators
Solve ax² + bx + c = 0 with real or complex roots, shown step by step.
Quadratic Equation Solver is a free online tool that solve ax² + bx + c = 0 with real or complex roots, shown step by step. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Calculators
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 3
- Works offline
- Yes, after the first visit
About Quadratic Equation Solver
The discriminant, b² − 4ac, tells you the shape of the answer before you compute it: positive means two real roots, zero means one repeated root, negative means a complex conjugate pair. The vertex is also given, since for most practical problems — projectile height, profit maximization — the turning point is what you actually wanted.
How to use it
- Enter a, b and c.
- Results update the moment anything changes.
The 3 settings
| Setting | What it does | Default |
|---|---|---|
| a | A numeric value. | 1 |
| b | A numeric value. | -3 |
| c | A numeric value. | 2 |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | a, b, c |
Questions
What do complex roots mean in a real problem?
Usually that the curve never crosses zero. If you are solving for when a ball hits the ground and get complex roots, the ball as modeled never gets there — check the signs on your inputs.
Is the arithmetic exact?
It uses double-precision floating point — about 15 significant figures, far more than the inputs justify. Displayed rounding is cosmetic; the underlying numbers are not rounded between steps, so chained results do not drift.