Calendar days and date offsets
Find the calendar-day gap between two dates and a separate date obtained by adding or subtracting days. Weekends remain part of the calendar count.
Understand the numbers · Make life easier
Age on a date
Find completed age on any selected date. You do not have to use today as the reference date.
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Completed age
26years old
The result counts birthdays already passed: completed years, rather than traditional nominal age.
Time since birth9,775 days
Uses completed years of age. For a February 29 birthday in a non-leap year, the birthday is treated as passed on March 1. This is not a legal age determination.
Method and scope
Subtract birth year from reference year and subtract another year if the birthday has not yet occurred. This is completed age, rather than traditional nominal age.
The age describes birthdays already reached by the reference date. Check that the date is not before the birth date.
For a February 29 birth, the non-leap-year transition is treated as March 1. Legal age and institution-specific eligibility may follow different rules.
What this helps you do
Find completed age on any selected date. You do not have to use today as the reference date.
What to enter
Start with date of birth, then fill the other relevant fields in the units shown. The field hints explain the required format and examples.
How the calculation works
Subtract birth year from reference year and subtract another year if the birthday has not yet occurred. This is completed age, rather than traditional nominal age.
Worked example
Someone born on 2000-12-10 is 25 on 2026-11-03. They turn 26 on 2026-12-10.
Understanding the answer
The age describes birthdays already reached by the reference date. Check that the date is not before the birth date.
Scope and limitations
For a February 29 birth, the non-leap-year transition is treated as March 1. Legal age and institution-specific eligibility may follow different rules.