How do I calculate my age?

Enter your date of birth and the calculator will instantly show your age in years, months, and days.

Can I calculate age for any past date?

Yes, the age calculator works for any valid date of birth in the past.

Age Calculator – Find Exact Age from Date of Birth

Enter your date of birth to instantly calculate your exact age in years, months, and days. Perfect for forms, documents, and quick reference.

What is an Age Calculator?

An Age Calculator helps determine the exact age of a person or object based on the date of birth or starting date. It calculates the years, months, and days from the provided date to the current date or another specified date. This is useful for birthdays, eligibility verification, insurance, or historical research.

Calculation Type

Calculate Age

Birth Date

Current Date

Find Birth Date

Age (Years)

Months (Optional)

Days (Optional)

Reference Date

Find End Date

Target Age (Years)

Months (Optional)

Days (Optional)

Start Date (Birth Date)

How Does the Age Calculator Work?

The user inputs a birthdate or start date and optionally an end date (defaulting to the current date). The calculator compares the dates by subtracting the earlier date from the later date, accounting for months and leap years to deliver an accurate age breakdown in years, months, and days. Some age calculators also calculate next birthdays or days until a certain age.

1. Calculate Age

Calculates the age in years, months, and days between a birth date and a given end date (default is the current date).
Breakdown:

Subtract birth year from end year to get full years.
Subtract birth month from end month to get months (if current month is less, subtract one year and add 12 months).
Subtract birthday from end day to get days (if current day is less, subtract one month and add days in previous month).

Formula (conceptual): Age = (End Year - Birth Year) - Adjustments in years, months, days
Excel example using DATEDIF:

Years = DATEDIF(BirthDate, EndDate, "Y")
Months = DATEDIF(BirthDate, EndDate, "YM")
Days = DATEDIF(BirthDate, EndDate, "MD")

2. Find Birth / Beginning Date

Calculates the birth or start date given the end date and age.
Reverse calculation from age and end date: Birth Date = End Date - Age (years, months, days)
Practically, subtract years, months, and days from the end date to get the birth date.

3. Find End Date

Calculates the end date given the birth date and age.
Add the age (years, months, days) to the birth date: End Date = Birth Date + Age (years, months, days)

Summary

The age calculation relies on counting full years, months, and days between two dates. Adjustments for month and day borrowing handle uneven month lengths and leap years to give accurate age in years, months, and days. These formulas ensure precise age calculation for various use cases such as legal age verification, event planning, or historical research.