How to use this calculator
Interval notation describes sets of real numbers using endpoints. Brackets include an endpoint and parentheses exclude it. A union combines intervals. This tool also merges overlaps while keeping track of whether a touching boundary belongs to the set.
The method
Enter the values in the labeled fields, check the units or selected mode, and choose Calculate. The result includes the applicable working and a breakdown or visual when useful. Change an input and calculate again to update the result.
Inequality or interval: -2 <= x < 5
Interval notation: [-2, 5)
-2 <= x < 5
Scope and limitations
Simple numeric inequalities and unions of intervals only; it is not a solver for expressions such as x^2 > 4. Infinity endpoints must be open. Reversed endpoints are rejected.
Common questions
Can infinity use a square bracket?
No. Infinity is not a real-number endpoint that can be included. Use (-inf, ... or ..., inf).
What does U mean?
U means union: any number that belongs to at least one of the intervals is in the combined set.
References & further reading
External references provide background, not an endorsement of this implementation. See our methodology for numerical conventions and limitations.