Interval Notation Calculator

(−∞, ∞), always with parentheses since infinity is never included.

Build interval notation from endpoints and inclusivity.

Lower bound

Upper bound

Lower endpoint

Upper endpoint

Interval [2, 5)

Formula: [ ] = included, ( ) = excluded

Step-by-step with your numbers:

1. Values used:

2. Lower bound = 2

3. Upper bound = 5

5. Interval = [2, 5)

Did we solve your problem today?

Interval notation compactly describes a range of numbers using brackets and parentheses.

The math behind it

Square brackets [ ] include the endpoint; parentheses ( ) exclude it. So [2, 5) means 2 ≤ x < 5.

Lower 2 included, upper 5 excluded → [2, 5).

How do I write 'all reals'?

(−∞, ∞), always with parentheses since infinity is never included.