Next Birthday Calculator
Calculate the next birthday date and the number of days until it.
Calculator
Results
How it works
Calculate the next birthday date and the number of days until it.
Example
| Example | Result |
|---|---|
| With a May 20 birthday and Sep 19, 2026 reference date, the next birthday is May 20, 2027. | See calculator |
Important notes
- Calendar calculations use Gregorian calendar rules.
- Business-day calculations exclude Saturday and Sunday unless stated otherwise.
- Time-zone calculations depend on the browser's IANA time-zone data.
- For planning purposes, verify dates and times when a contractual or legal deadline is involved.
Frequently Asked Questions
Can I use a custom reference date?
Yes. That makes the result reproducible instead of relying on the visitor’s device date.
How to use this calculator
What to enter
Enter or select the following as requested: Date of birth; Today / reference date. Follow the units, valid ranges, examples, and options displayed beside each field.
What the result means
The date or duration result is calculated from the entered dates, times, calendar rules, and exclusions. Check inclusive versus exclusive counting, time zone, daylight-saving changes, and whether weekends or holidays are excluded.
When to use it
Use this to plan a date, measure elapsed time, or estimate a deadline. Verify the relevant calendar, location, and legal or workplace rules when they affect the answer.