Quadratic Formula Calculator

Enter the coefficients a, b and c of a quadratic equation ax² + bx + c = 0, and Quadratic Formula Calculator solves it for x. It handles real roots and complex roots, and shows the answer with fractions and decimals.

What you get
• Coefficients a, b and c, with negative values allowed
• Real roots shown as decimals
• Complex roots shown as a fraction with a ± i term, plus decimal values
• A clear message when a is zero, because the equation is then not quadratic

Where it helps
• Checking homework on quadratic equations
• Finding where a parabola crosses the x-axis
• Seeing from the discriminant whether an equation has real or complex solutions
• Checking a hand calculation with the quadratic formula

Made for daily use
• Light and dark theme
• 28 languages, with right-to-left layout where it belongs

A new app
Built on the Calculator.io calculator engine. A More calculators link opens the full Calculator.io app, with 170+ tools for math, money, health and dates.

The app is supported by banner ads. Results are computed numerically and rounded, so very large or very small coefficients may show approximate values.