Math

Quadratic Equation Calculator

Find the roots of a quadratic equation of the form ax squared plus bx plus c equals zero.

—

This result gives the values of x where the equation equals zero, shown as two roots with their discriminant.

Formula

Roots = (−b ± square root of (b squared − 4ac)) ÷ 2a. The value b squared − 4ac is the discriminant.

How it works

Enter a, b, and c with a not zero. The calculator checks the discriminant: positive gives two real roots, zero gives one repeated root, negative gives no real roots.

Worked example

For example, with a = 1, b = -5, and c = 6, the discriminant is 25 - 24 = 1, and the roots are x = 3.0000 and x = 2.0000.

FAQs

What does the Quadratic Equation do?
It takes the values you enter and works out the quadratic equation for you, showing the result straight away.

What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.

Can I use the result for homework or everyday math?
Yes. It is a general-purpose math helper; for exam or professional work, still check the steps against your own working.

Related calculators

Absolute Value Calculator

Arithmetic Sequence Calculator

Circle Area Calculator

Fast results

Instant result, no sign-up.

Free to use

All tools are free.

Formula shown on the page

Each page shows the formula it uses, so you can check the result yourself.

Works on mobile

Built for phone browsers.

Start with a free calculator

Search, pick a calculator, and get an instant result. No sign-up, no download.

Browse categories Read the blog