Your exact age to the day, how many days you’ve lived, and time until your next birthday. All in your browser.
How to use the age calculator
Enter a birth date and the calculator returns your exact age in years, months, and days, plus the total number of days, weeks, and hours since that date. Set a different “as of” date to calculate an age at any point in the past or future.
Common reasons to calculate an age precisely
Age calculators come up more often than people expect: checking eligibility for a program or benefit, filling in forms that ask for age in years and months, planning a milestone birthday, or working out a child’s age in weeks for a health check.
Tips for exact results
Dates near a birthday are where mistakes happen, so use the day-level output rather than rounding up. Remember leap years add a day roughly every four years, which this tool accounts for automatically.
How the age calculator works
The calculator finds the exact span between two dates by counting the difference in years, months and days, then expressing the remainder in total days, total weeks and even the total hours you have been alive. It accounts for the uneven length of months and leap years, so “February 29 to March 1” is handled correctly rather than guessed.
Besides your current age, it can measure the gap between any two dates — useful for anniversaries, project timelines or eligibility checks where a precise day count matters.
Common uses
- Birthdays and milestones — find your exact age to the day, and how many days until your next one.
- Eligibility — confirm age requirements for voting, driving, retirement or age-restricted services.
- Anniversaries — see how long you have been at a job, in a relationship or in a home.
- Date differences — measure the length of any event or waiting period in days.
Frequently asked questions
Is the age accurate across leap years?
Yes. The tool uses the real calendar, including February 29, so multi-year spans are exact.
Why do months and days sometimes look odd?
Because months have different lengths, the calculator counts whole months first and then the leftover days, which can make a span look uneven even when it is correct.
Can it count backwards?
Yes. If the end date is earlier than the start date, it shows the difference as a negative span.
Does it need an internet connection?
No. All date math runs in your browser the moment you pick the dates.
Can I work out someone’s age from just a birth year?
You can, but the result will be approximate to the year. For an exact age to the day you need the full birth date, including the month and day.
Can it also count time until a future date?
Yes. Enter a future date as the end date and it shows the span remaining, which is handy for planning ahead to a deadline or a trip.
The same interval in different units
| Unit | What it counts | Use it for |
|---|---|---|
| Completed years | Anniversaries passed | Legal age, forms, eligibility |
| Years, months, days | Calendar breakdown | Everyday answers, records |
| Total months | Calendar months | Tenancy, subscriptions |
| Total weeks | Seven-day blocks | Project timelines |
| Total days | Elapsed days | Deadlines, notice periods |
| Total hours | Elapsed hours | Short intervals, shift work |