Calculator
Age calculator
Calculate the exact calendar age between a date of birth and any comparison date.
Your dates
Both entries are calendar dates without a time. The result updates automatically.
Your result
Complete both valid date fields to calculate the calendar age.
How age is calculated
The calculator finds complete calendar years first, then complete calendar months, followed by the remaining days. Different month lengths and leap years are included.
A 29 February birthday is observed on 28 February in non-leap years. Hours, minutes and seconds are derived only from complete calendar days.
Important notes
- ✓The comparison date may be in the past or future.
- ✓Dates are processed without a time or time-zone shift.
- ✓A second-accurate biological age cannot be determined without a birth time.
Frequently asked questions
How is my exact age calculated?
Calendar-wise: complete years first, then complete months, then the remaining days.
Why do remaining days vary between months?
Months contain 28, 29, 30 or 31 days. Moving into a shorter month clamps the date to its final valid day.
How are leap years handled?
The Gregorian rule is used, including the century and 400-year exceptions.
How is a 29 February birthday handled?
In a non-leap year, 28 February is treated as the birthday.
Are the displayed seconds exact?
No. They are total calendar days multiplied by 86,400 because no birth time is entered.