Age Calculator
Calculate exact age from date of birth to today or any selected date.
Simple, fast and clear
Enter your values, review the result, and read the formula used so the calculation is easy to understand.
Age Calculator
Use the fields below to calculate your result instantly.
What is the Age Calculator?
An age calculator finds exact age between a date of birth and a selected date. It shows completed years, months and days, which is more useful than simply subtracting birth year from current year.
Age calculation needs calendar adjustment because months have different lengths and leap years can affect day counts. The calculator handles incomplete months and days so the result is easier to read.
This tool is useful for birthdays, school forms, eligibility checks, document preparation, insurance forms and any situation where exact age matters.
How we calculate the result
Formula: Age = selected date - date of birth, adjusted into completed years, months and days
The calculator first compares the year, month and day values from both dates. If the current day is earlier than the birth day, it borrows days from the previous month. If the current month is earlier than the birth month, it borrows one year.
This adjustment gives completed years, completed months and remaining days instead of a rough decimal age. It also avoids common mistakes around birthdays that have not occurred yet in the selected year.
When to use this calculator
Use this calculator for exact age, age at a future date, age at an event date and form-filling where years, months and days are required.
Input tips for better results
Enter the date of birth and the date on which you want to calculate age. For official uses, match the date format with the document requirement.
Compare completed years with total months or days when the exact duration matters, such as eligibility or planning.
Limitations of this calculator
This calculator counts calendar difference. Official age rules may use local cutoff dates or document-specific rules.
Real-world example
Someone born on 10 May 2000 has a different exact age on 9 May 2026 than on 10 May 2026.
Mistakes to avoid
Do not ignore the day and month. Age in completed years changes only after the birthday has passed.
Frequently Asked Questions
Why not subtract birth year only?
That ignores whether the birthday has happened yet in the selected year.
Can I calculate age on a future date?
Yes. Use the selected date field if the page provides one.
Does leap year affect age?
Leap years can affect day counts, so calendar-based calculation is more accurate.
Helpful tips
- Enter the date of birth and the date on which you want to calculate age. For official uses, match the date format with the document requirement.
- Compare completed years with total months or days when the exact duration matters, such as eligibility or planning.
- Do not ignore the day and month. Age in completed years changes only after the birthday has passed.
- This calculator counts calendar difference. Official age rules may use local cutoff dates or document-specific rules.
Before you rely on the result
This calculator counts calendar difference. Official age rules may use local cutoff dates or document-specific rules. Keep the input values with the result so you can review the assumption later.