A free age calculator that runs entirely in your browser. Enter a date of birth and instantly see the exact age in years, months, and days — plus total months, weeks, days, and hours lived, and a live countdown to the next birthday (including which weekday it falls on). You can also calculate age as of any past or future date. Nothing is uploaded — all the date math happens on your device.
Age in other units
All calculations run in your browser using your device’s local date — nothing you type here ever leaves your device. Totals count whole calendar days between the two dates; hours are total days × 24.
How to use this age calculator
Pick the date of birth using the month, day, and year fields — no fiddly date picker required, and it works the same in every browser. The exact age appears instantly in years, months, and days, along with the age expressed as total months, weeks, days, and hours. By default the age is calculated as of today (your device's local date), but you can change the "age at" date to any past or future day — handy for forms that ask "age as of" a specific date, checking how old someone was on a historical date, or working out an age on an upcoming deadline. You'll also see a countdown to the next birthday and which weekday it lands on. Looking for other quick calculators? Browse all the free GeoParrot tools.
How age is calculated (years, months, days)
The calculator uses calendar-correct date math, the same way age is counted in everyday life:
- Years increase only when the birthday (month and day) has actually passed in the target year.
- Months count whole calendar months since the last birthday.
- Days are what's left after full months are counted. When the day-of-month of the target date is smaller than the birth day, the tool "borrows" the real length of the previous calendar month (28, 29, 30, or 31 days) instead of assuming every month has 30 days — that's what makes the result exact.
Because months have different lengths, an age like "1 month 30 days" and "2 months" can describe nearly the same span depending on which months are involved; this tool always resolves it consistently by counting full months first, then leftover days. Total days are counted as whole calendar days between the two dates, total weeks are total days divided by 7 (rounded down), and total hours are total days × 24. If the date of birth is on February 29, the next birthday in a non-leap year is treated as March 1. Need the result as a share or change in percent? Try the percentage calculator.
Frequently asked questions
How do I calculate my exact age?
Subtract your birth date from today's date using calendar months, not 30-day months. Count full years up to your last birthday, then full months since that birthday, then the remaining days — borrowing the actual length of the previous month when needed. That's exactly what this tool does automatically: enter your date of birth and it shows your precise age in years, months, and days.
How many days old am I?
Enter your date of birth above and check the Total days row — it counts every calendar day from your birth date to today, correctly handling leap years. As a rough guide, each year of age is about 365.25 days, so a 30-year-old is around 10,957 days old.
When is my next birthday?
The tool shows a live countdown: how many days remain until your next birthday and which day of the week it falls on. It's computed from today's date on your device, so it's always current when you load the page.
Is this age calculator free and private?
Yes — it's completely free, with no signup. All the date math runs locally in your browser, so the dates you enter are never sent to any server.
More free tools
Browse the full set of free GeoParrot tools, including the percentage calculator for quick percent math.