Quadratic Equation Calculator
Solve ax squared plus bx plus c equals zero and see the discriminant and both roots.
Quick answer: enter your details below and click Calculate — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
Q
Calculators
Enter your details below.
How to use
- Enter a, the coefficient of x squared.
- Enter b and c.
- Calculate to see the discriminant and the roots.
About this tool
Enter the three coefficients a, b and c. The tool first works out the discriminant, b squared minus 4ac, which tells you whether real roots exist. When the discriminant is zero or positive, it applies the quadratic formula, negative b plus or minus the square root of the discriminant, all divided by twice a.
Frequently asked questions
What if a is zero?
Then the equation is not quadratic at all, it is a straight-line equation, so the tool says so instead of giving quadratic roots.
What does a negative discriminant mean?
It means there are no real roots, because you cannot take the square root of a negative number in ordinary real arithmetic.