Find the roots of a quadratic equation from its three coefficients.
Quadratic Formula Calculator
Form
Results
Discriminant
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Table of Contents
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What is Quadratic Formula?
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How to Use This Calculator
- Enter or select A, B, C.
- Check the unit beside each measurement. For a percentage or rate, use the scale and time period stated in the form.
- Choose Calculate, then compare the output with the formula and example below. If you change a value or option, calculate again to update the result.
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Formula Used
x = (−b ± √(b²−4ac))/(2a)
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Variables Explained
| Input | What it means |
|---|---|
| A | A value or coefficient in the formula above; keep the displayed position and sign. |
| B | A value or coefficient in the formula above; keep the displayed position and sign. |
| C | A value or coefficient in the formula above; keep the displayed position and sign. |
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Worked Example
For x² − 5x + 6 = 0, the roots are 2 and 3.
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Why Use This Calculator?
Find roots even when a quadratic does not factor neatly into integers.
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Common Mistakes
- The leading coefficient cannot be zero. A negative discriminant means the roots are complex.
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Frequently Asked Questions
Should I round numbers before calculating?
Keep the original input precision through the calculation and round the final answer to the precision you need. Rounding an intermediate result can change later steps.
Why can a manual calculation differ slightly?
Check the operation, units, signs and rounding first. Equivalent fractions or expressions can look different while representing the same value.
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