📅 DATES

Date Calculator

Days between dates, add/subtract days, age calculator, event countdowns — all in one place.

Start Date

End Date

days apart

Start Date

Days to Add (+) or Subtract (−)

resulting date

Date of Birth

Calculate Age As Of

years old

Event Name

Event Date

days to go

1 year = 365 or 366 days (leap years)

1 month = 28–31 days depending on month

1 week = 7 days exactly

Leap year rule = divisible by 4, except centuries unless divisible by 400

Business days = weekdays only (Mon–Fri)

Unix epoch = January 1, 1970