All calculators
Free browser-based tools for set theory and list operations. Pick a calculator below — no account required, results stay on your device.
Sets & lists
Set Operations
Compute the union, intersection, or difference of two sets with formatting options and worked examples.
Open calculator →Interval Operations
Union and intersection of number-line intervals in bracket notation — for continuous ranges on ℝ.
Open calculator →Cartesian Product
Generate every ordered pair from two sets (A × B). Ideal for combinations, grids, and product spaces.
Open calculator →List Unique
Remove duplicates from a list while preserving first-seen order — turn messy lists into clean unique values.
Open calculator →Sort & Reverse
Sort items A–Z or Z–A, or reverse the current order. Works with text and natural number ordering.
Open calculator →Date & time
Date Difference
Count days between two calendar dates, with weeks and a years/months/days breakdown.
Open calculator →Add / Subtract Date
Shift a start date forward or backward by years, months, and days.
Open calculator →Weekday
Find which day of the week a given date falls on.
Open calculator →Week Number
Get the ISO 8601 week number, week-year, and Monday–Sunday range for a date.
Open calculator →Every calculator runs locally in your browser. Start with set operations for list union/intersection, or interval operations for number-line ranges.