About this tool
Solve a quadratic equation in the form ax² + bx + c = 0. This page explains the values requested and the method used so you can check whether the result fits your purpose.
How to use it
Enter a, b and c.
Press Calculate, then review the result and the method below. Use Reset to clear the values in the calculator panel.
Method used
x = (−b ± √(b² − 4ac)) ÷ 2a.
Important assumptions and limits
Check that the units and values you enter are appropriate for your use case.
Maths note: Use consistent units and check the result against the method shown before relying on it.
Questions about this result
Are the values I enter sent to The Decimal Space?
No. This calculator processes the values in your browser. This page does not require a calculator account or a server-side save function.
Can I use this for an important decision?
Check the inputs, units, formula and any rounding. For a decision with legal, tax, financial, medical, engineering or safety consequences, use an official source or obtain advice from an appropriately qualified professional.
Why might a result differ from another calculator?
Different tools can use different inputs, rounding, units, assumptions or formulas. Compare the calculation method rather than relying only on a displayed number.