Frequently Asked Questions
Everything you need to know about the Inequality Calculator.
How does the inequality calculator work?
Type in your inequality and it solves step by step, showing the solution as an inequality, an interval, and a number line.
Is it free?
Completely free, no sign-up, downloads, or limits.
Does it handle quadratic inequalities?
Yes, it finds the roots and builds a sign chart to determine the correct solution intervals.
What about compound inequalities?
Yes, inequalities like -3 < 2x + 1 < 5 are split, solved, and recombined correctly.
Why does the sign flip sometimes?
Multiplying or dividing both sides by a negative number reverses the inequality direction — the calculator highlights this step explicitly since it's the most common mistake.
What does interval notation mean?
A compact way to write a solution set, like (2, ∞) for "all values greater than 2" — shown alongside the inequality form.
What if there's no solution?
The calculator explains clearly when an inequality has no solution, rather than leaving the answer blank.
What if all real numbers satisfy it?
Cases like x² ≥ 0 are identified and explained as true for all real numbers.
Is my data stored?
No; everything runs in your browser and isn't stored or sent.
Does it work on mobile?
Yes, fully responsive; the number line and steps adapt to smaller screens.