Quadratic Equation Calculator

What this calculator does

A quadratic equation has the form ax squared plus bx plus c equals zero. This calculator solves for x and shows whether the roots are real or complex.

Formula used

The calculator uses the quadratic formula. x equals negative b plus or minus the square root of b squared minus 4ac, divided by 2a.

How to read the result

The discriminant decides the shape of the answer. Positive gives two real roots, zero gives one repeated root and negative gives a complex pair.

Assumptions

• a cannot be zero.
• Results are rounded for readability.
• Complex roots are shown in a plus or minus i form.

Sources and checks

This calculator uses a standard public formula. Where rules or thresholds can change, source links are listed on the relevant page.

Frequently asked questions