Age Calculator
Enter a date of birth to see your exact age and how many days until your next birthday. Change the “age at” date to calculate age on any past or future day.
Your numbers
How we calculate it
Age is the number of whole years between the two dates, then the whole months left over, then the remaining days. Dates are compared in UTC so time zones and daylight saving cannot change the answer.
For a February 29 birthday, the next birthday in a non-leap year is counted on February 28.
How to read your result
- Age is shown in years, months and days from the birth date to the chosen date.
- Next birthday shows how many days remain and which day of the week it falls on.
- Total days, weeks and months are useful for forms and milestones that count in those units.
- Leave the second date empty to use today.
Common mistakes
- Mixing up day and month when typing a date. The date box follows your browser’s format, so check it before reading the result.
- Forgetting that someone born on February 29 has a legal birthday of February 28 or March 1 depending on the place.
- Counting the birth day itself. Age counts completed years, not the days you have been alive plus one.
- Expecting a time-zone change to alter the answer. Dates are counted as calendar days.
Assumptions and limits
- Some countries count age differently (for example, traditional East Asian age systems). This tool uses the standard international method.
- Total weeks is the total days divided by seven, rounded down.
Frequently asked questions
How is age calculated exactly?
Count the full years since the birth date, then the full months since the last birthday, then the days since the last monthiversary.
What if I was born on February 29?
You have a birthday every four years on the calendar date; in other years we count February 28 for the next-birthday countdown.
Can I calculate age on a future date?
Yes. Put the future date in “Age at date” to see how old someone will be then.
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Worked example (a fixed example using the starting numbers, it does not change as you type)
Inputs: Date of birth = April 18, 1992; Age at date = October 24, 2026.
- Age 34 years, 6 months, 6 days
- Total months 414
- Total weeks 1,801
- Total days 12,607
- Next birthday Sunday, April 18, 2027 (176 days away)
- Born on a Saturday
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