How it works
The calculator works out a calendar-accurate breakdown between your date of birth and today — years, months and remaining days — the same way you'd naturally describe an age. A guard stops you entering a future date, since a birth date can't be later than today.
age = today − date of birth, expressed as years/months/days
next birthday = the next occurrence of your birth month/day from today
Worked example
Someone born 12 June 1994, as of 17 August 2026.
- Years: 2026 − 1994 = 32 years — August comes after June so no borrowing is needed.
- Months: August (8) − June (6) = 2 months.
- Days: 17 − 12 = 5 days.
- Total days lived: 11,754 days.
- This year's birthday (12 June 2026) has already passed, so the next birthday is 12 June 2027 — 299 days away.
The age is 32 years, 2 months, 5 days — 11,754 days lived, with 299 days until the next birthday.
Common questions
Why is my age in months sometimes higher than expected right after a birthday?
The month count only advances once the day-of-month has been reached — if today's day-of-month is earlier than your birth day-of-month, the calculator borrows a month (and counts the remaining days from the previous month) rather than showing a negative or fractional month. This is the same borrowing rule used for a calendar date subtraction.
Does this account for leap years?
Yes — the calculation works from real calendar dates rather than a fixed 365.25-day average, so leap days (29 February) are handled automatically wherever they fall between your date of birth and today.