# Calendars & Planners

Under ISO 8601, weeks start on Monday and week 1 of a year is the week that contains its first Thursday, so 1 January can fall in the last week of the previous year. Calendars also show day-of-year counts, leap years and movable dates such as Easter, and planners lay out schedules and events.

## Tools

No tools are available here yet.

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Category: [Time & Date Tools](https://techolm.com/date-time-tools)