Fast, free calculators and tools for everyday problems.
Calculate exact age in years, months, and days from a birth date and as-of date.
A quick overview to help you understand what this tool does and how to use it well.
Use this age calculator to find an exact age in years, months, and days based on a birth date and a chosen as-of date. This tool is useful for personal reference, forms, records, school or work requirements, and any situation where you need a precise age instead of a rough estimate.
By entering a birth date and an as-of date, you can quickly calculate a clear age breakdown and avoid doing calendar math by hand.
Fields marked with * are required.
Your result updates after a successful calculation.
Completed years
35
Age in full completed years.
Remaining months
10
Full remaining months after completed years are counted.
Remaining days
4
Remaining days after years and months are counted.
Precise age
35 years, 10 months, 4 days
Combined age shown as years, months, and days.
Age summary
Age as of April 19, 2026
Readable date reference for the age calculation.
See the formula, calculation method, and reasoning behind the result.
This calculator finds the difference between a date of birth and a selected as-of date, then breaks that difference into completed years, remaining months, and remaining days.
In general, the calculation works like this:
This produces a more precise result than simply subtracting one year from another. Exact age calculations need to account for month lengths, whether a birthday has already occurred, and leap years when applicable.
That makes this calculator useful when you need a clear calendar-based age result rather than just an approximate age in years.
Find the exact age for someone born on June 15, 1990, as of April 19, 2026. This example shows how the calculator measures completed years first, then adds the remaining months and days to give a more exact age result.
Example results
Common questions about this tool.
This version of the tool expects an explicit as-of date so the result reflects the exact date you want to measure against.
Yes. The calculator adjusts the result when the as-of date falls before the birthday in the selected year.
Age is calculated by finding the difference between a birth date and an as-of date, then expressing that difference in completed years, remaining months, and remaining days.
The as-of date tells the calculator the exact date on which age should be measured. This is helpful if you want to know your age today, on a future date, or on a past date for a form or record.
Yes. Completed years only tell you how many full birthdays have passed. Exact age includes the additional months and days beyond the last birthday.
Yes, an exact age calculation should account for real calendar differences such as leap years and varying month lengths to produce a more accurate result.
Yes, you can enter a future as-of date to estimate how old someone will be on that date.
Subtracting the years gives only a rough result. It does not account for whether the birthday has occurred yet in the selected year, and it does not include the remaining months and days.