BdayChecker Blog
Guides that go with our tools: how to keep birthdays in your calendar, how to work out an exact age, what the birth month symbols mean and where the traditions come from. Every fact is checked against its source.
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Planners · October 21, 2026How to Add Birthdays to Google Calendar, iPhone and Outlook
Every birthday in your calendar, with a reminder, in a few steps.
Age and time · October 21, 2026How to Calculate Your Exact Age by Hand and in Excel
The DATEDIF formula, and the same sum worked out by hand.
Zodiac and numerology · October 21, 2026Is 13 a Lucky Number?
Why 13 is feared in some places and lucky in others.