Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
Root 1
3.000000
Root 2
2.000000
Discriminant
1.0000
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter a.
- 2Enter b.
- 3Enter c.
- 4Read your root 1 on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Computes both roots of a quadratic and reports complex roots when the discriminant is negative.
Worked example
Using the values the calculator loads with:
Inputs
- a: 1
- b: -5
- c: 6
Results
- Root 1: 3.000000
- Root 2: 2.000000
- Discriminant: 1
What each field means
Inputs
- a
- The a used in the calculation. Starts at 1 so you have a working example on load.
- b
- The b used in the calculation. Starts at -5 so you have a working example on load.
- c
- The c used in the calculation. Starts at 6 so you have a working example on load.
Results
- Root 1
- Returned as a plain value and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Root 2
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Discriminant
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the quadratic equation solver work?
Computes both roots of a quadratic and reports complex roots when the discriminant is negative.
What do I need to enter?
3 values: a, b, and c. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the root 1 result mean?
It is returned as a plain value and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are rounded for display; the underlying calculation keeps full precision.
Who is this tool for?
It's built for students, developers, and anyone who needs the answer right now without setting up a spreadsheet.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Quadratic Equation Solver. Retrieved from https://www.revenuelab.fyi/toolbox/quadratic
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/quadratic" target="_blank" rel="noopener">Quadratic Equation Solver — RevenueLab</a> (2026).</p>
Source: [Quadratic Equation Solver — RevenueLab](https://www.revenuelab.fyi/toolbox/quadratic) (2026).