Age Calculator

Subtract the birth year, month and day from the reference date, borrowing months and days exactly like calendar subtraction. For example, from 15 Jan 2000 to 29 Sep 2026 is 26 years, 8 months and 14 days. Total days lived is the plain day count between the two dates.

In non-leap years this calculator celebrates the birthday on February 28, the common convention (some families prefer March 1). Age arithmetic still uses the real Feb 29 birth date, so totals stay exact either way.

Differences come from time zones and whether institutions count the birth day itself. This calculator uses calendar dates without time zones: the difference between two midnights, which matches how most forms and IDs treat age.

Yes — set the optional Age as of field. Use a past date for throwback ages (for example, how old you were at graduation) or verify eligibility cut-offs. The birth date itself must not be in the future relative to the reference date.

Term insurance premiums rise steeply with entry age — buying at 25 versus 35 can halve lifetime premiums. Similarly, retirement corpus math depends on years left to compound. Knowing your exact age sharpens both calculations.

Your birthday this year is compared with the reference date: if it has passed, the countdown targets next year's birthday. The day count is exact calendar days, and a birthday happening today shows a celebration state with zero days to go.