Birthday Calculator
Find exact age, total days, and the time until the next birthday from any birth date and reference date.
Omni's birthday tools use calendar-aware date math so month lengths and leap years are handled correctly.
Age and Birthday
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Run the calculation to see the exact age and next birthday countdown.
Quick Answer
The calculator shows the exact calendar age on the chosen date and tells you how long remains until the next birthday.
How to Use It
- Enter the birth date.
- Enter the reference date.
- Click Calculate.
- Read the exact age and the next birthday countdown.
Formula
Age = calendar difference between birth date and reference date
Next birthday = next occurrence of the birth month and day after the reference date
Worked Examples
Example 1: Someone born on 21 April 1990 is 35 years old on 29 March 2026, with the next birthday 23 days away.
Example 2: A birthday in February stays exact even across leap years because the calculator uses calendar dates.
Example 3: The countdown shrinks to zero on the birthday itself.
How to Interpret the Result
| Output | Meaning |
|---|---|
| Exact age | Years, months, and days on the selected date. |
| Total days | Useful for milestone tracking and planning. |
| Next birthday countdown | How long is left until the next birthday arrives. |
Frequently Asked Questions
Related Calculators
References
- OmniCalculator reference page
- The reference calculator uses date subtraction to find age and the next birthday.
- Last reviewed: March 2026.