Quadratic Equation Calculator

Solve any quadratic equation Ax² + Bx + C = 0 instantly with step-by-step results.

What this calculator does

The discriminant D = b² - 4ac determines the number of solutions.

When to use this calculator

Use this calculator whenever mental arithmetic introduces uncertainty — particularly when the result will inform a decision rather than just satisfy curiosity. Even confident mathematicians use calculation tools when precision matters.

Common mistakes

A common mistake is applying the formula in the wrong direction — particularly with percentage and ratio problems, where the part and the whole can be mistakenly swapped. Check which value is the reference (the 'whole') before entering inputs.

Real-world scenarios

A student checks their overall module grade before results day: 3 assignments scored 72%, 68%, and 81% — the calculator confirms the weighted average and tells them what score they would need on the final exam to achieve a target grade.

Frequently asked questions

What is the quadratic formula?

x = (-b ± √(b²-4ac)) / 2a