🔒 Privacy: everything runs in your browser. Nothing is uploaded.
About this age calculator
An age calculator answers a simple question precisely: exactly how old is someone on a given date? Forms for visas, school enrollment, insurance, sports leagues and retirement plans often ask for age "as of" a cutoff date rather than today, and getting it wrong by a day can matter. Enter a date of birth and any target date to get the age in years, months and days.
You also get the total number of days and weeks lived and a countdown to the next birthday. People born on 29 February are handled by the calendar rules of your browser: in non-leap years the birthday rolls over to 1 March. Your birth date is not stored or sent anywhere — the calculation happens on your device.
Different cultures count age differently. The international convention used here starts at zero at birth and increases on each birthday. Traditional East Asian age reckoning, still referenced informally in some places, counts a newborn as one and adds a year at the new year, so results can differ by one or two years. Official documents nearly always use the international method. The calculator is also handy for non-human ages: enter the start date of a company, a website domain, a relationship or a pet’s adoption to see exactly how long it has been, down to the day.
How to use it
- Enter the date of birth.
- Leave "Age on date" as today, or set a cutoff date.
- Read the age, total days and next-birthday countdown.
FAQ
How is age in months and days calculated?
Full calendar years are counted first, then full months, then remaining days, the way people normally state age.
Can I calculate age at a past or future date?
Yes, change the "Age on date" field.
What about leap-day birthdays?
In non-leap years the next birthday is shown as 1 March.
Is my birth date saved?
No, nothing is stored or uploaded.