---
title: Union and Intersection of Intervals Calculator
description: Free calculator for union and intersection of real-number intervals in bracket notation.
---

# Interval Union & Intersection Calculator

Compute **A ∪ B** and **A ∩ B** for intervals on the real line. Enter values like `[1, 5)`, `(0, 1]`, or `(-inf, 3]`.

Site: [https://setcalculators.com/interval-operations.html](https://setcalculators.com/interval-operations.html)

## Notation

- `[a, b]` — closed (includes endpoints)
- `(a, b)` — open (excludes endpoints)
- Mixtures such as `[a, b)` are supported
- Unbounded ends: `-inf` / `inf` or `−∞` / `∞`

## Examples

- Union: `[1, 5] ∪ (4, 10] = [1, 10]`
- Intersection: `[0, 5) ∩ [3, 8] = [3, 5)`
- Disjoint union: `[0, 1] ∪ [2, 3] = [0, 1] ∪ [2, 3]`

## Related

- [Set operations (list items)](https://setcalculators.com/) — discrete unions/intersections
- [All calculators](https://setcalculators.com/calculators.html)