Perpetual Calendar
Interactive calendar with world holidays, week numbers, and historical events on any date.
May 2026
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How to Use This Tool
- Navigate to any year and month using the calendar controls.
- Click any date to see detailed information including day of week and week number.
- Highlighted dates show world holidays and observances.
- Use the search feature to find specific dates or holidays.
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Frequently Asked Questions
What is a perpetual calendar?
A perpetual calendar is a calendar that can display any date across any year, past or future. Unlike annual calendars that show only one year, a perpetual calendar lets you explore dates across centuries.
What holidays does this calendar show?
The calendar includes major international holidays, national observances from various countries, and cultural celebrations. Holiday coverage continues to expand.
Can I find what day of the week a historical date was?
Yes. Navigate to any date in history and the calendar will show you exactly what day of the week it was. This is useful for historical research and genealogy.
How are week numbers calculated?
Week numbers follow the ISO 8601 standard, where week 1 is the week containing the first Thursday of the year. This is the international standard used in most countries.
How far back can this calendar go?
Our perpetual calendar supports dates from year 1 to 9999. It uses the Gregorian calendar system and can tell you the day of the week for any date in that range.