Age Calculator
Your exact age in years, months and days — plus total weeks, days and hours, and a countdown to your next birthday.
Runs entirely in your browser. Nothing you type here is uploaded, stored or logged.
What “exact age” actually means
Age is counted in completed units. You are 34 until the moment your 35th birthday arrives — not 34.7 rounded up. This calculator follows that convention: it reports completed years, then the completed months since your last birthday, then the leftover days.
That is why you should be wary of the quick method of dividing total days by 365.25. It's close, but it drifts by a day or two around leap years, which is exactly when people tend to be checking a cut-off date.
When the exact number matters
- School enrolment. Most systems use an age-on-a-fixed-date rule, so set the “age at” field to the cut-off rather than today.
- Visas and travel. Child, youth and senior fares are usually assessed on the date of travel, not the date of booking.
- Insurance and medical forms. Premium bands and dosage guidance often switch on a birthday, so being a week short changes the answer.
- Legal documents. Contracts, licences and consent thresholds are defined in completed years.
Reading the totals
The four figures below the main result are the same span expressed differently. Total days is the honest one — an exact count including every leap day. Total months counts completed calendar months, and total weeks is simply days divided by seven. Parents of small children usually want months; anyone tracking a milestone usually wants days.
A note on birthdays that fall on 29 February
Roughly one person in 1,461 is born on a leap day. Legally, most jurisdictions treat 1 March as the birthday in common years, and that's the convention used here for the countdown. Your completed-years age still increases exactly once per year, as you'd expect.
Frequently asked questions
How is exact age calculated?
Calendar-aware subtraction, not division. We take the years between the two dates, then the months, then the days, borrowing from the previous month where needed. That is why the answer differs slightly from “days ÷ 365.25” — months have different lengths, and this method matches how age is legally and conventionally counted.
What happens if I was born on 29 February?
In non-leap years your birthday is treated as 1 March for the countdown, which is the most common civil convention. Your age in completed years still increments once per year, and the total-days figure is exact either way.
Can I calculate age at a past or future date?
Yes. Change the “age at” date from today to any date. This is useful for eligibility checks — school year cut-offs, insurance bands, visa age limits — where the question is how old someone will be on a specific day rather than right now.
Why does my age in months look larger than expected?
Total months counts every completed month since birth, so a 30-year-old is 360+ months old. The “years, months, days” line is the one you want for everyday use; the totals below it are alternative views of the same span.