How to use this quadratic equation calculator
- Enter the coefficient a — the number in front of x². It must not be 0, or the equation is not quadratic.
- Enter the coefficient b — the number in front of x. Use 0 if there is no x term.
- Enter the coefficient c — the constant term. Use 0 if there is none.
- Press Calculate. The tool shows the rewritten equation, the discriminant Δ = b² − 4ac, the quadratic formula with your numbers substituted, and both roots x₁ and x₂.
A quadratic equation has the form ax² + bx + c = 0. The sign of the discriminant Δ = b² − 4ac decides what you get back: Δ > 0 gives two distinct real roots, Δ = 0 gives one repeated real root, and Δ < 0 gives a conjugate pair of complex roots written as x = p ± qi. All three cases are handled here, in your browser — nothing is uploaded.
More math tools are in Math & Statistics.