Next birthday
Next birthday: use date of birth, from date, february 29 in non-leap years. Review the formula, worked example and calculation steps.
Inputs
Use the units shown—
Enter your values and select Calculate.
Formula & explanation
Find the next anniversary on or after the supplied Gregorian date.
Variables & units
- Date of birth
- Gregorian date
- From date
- Gregorian date
- February 29 in non-leap years
- Select an option
Worked example
A June 15 birthday viewed on November 7, 2026 next occurs on June 15, 2027.
Assumptions
Uses date-only Gregorian arithmetic. Today’s birthday is counted as zero days away.
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
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