Age Calculator
Find out exactly how old someone is in years, months and days.
Enter a valid date of birth to see the result.
About this tool
This calculator computes exact age by counting full years, months and days between a date of birth and a reference date, correctly handling different month lengths (28 to 31 days) and leap years — something a simple "days ÷ 365" estimate gets wrong.
Exact age calculations come up more often than you might expect: eligibility checks for school enrollment, retirement or pension age, legal age of majority, visa and immigration applications, and even pet or livestock age tracking all depend on precise year/month/day figures rather than rough estimates.
By default the calculator compares your date of birth to today, but you can set the second date to any point in the past or future to find out how old someone was, or will be, on a specific day.
Worked example
- 1Enter the date of birth in the first field.
- 2Leave the second field as today's date, or change it to any date you want the age calculated for.
- 3The result breaks the difference down into full years, remaining months, and remaining days, plus the total number of days.
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Frequently asked questions
- How is exact age calculated?
- The calculator counts the full years, months and remaining days between your date of birth and the chosen date, accounting for varying month lengths and leap years — it doesn't just divide the number of days by 365.
- Can I calculate age as of a specific date?
- Yes, change the second date field to any date — past or future — to see what your age was, or will be, at that point in time.
- Why is my age in days different from years × 365?
- Multiplying years by 365 ignores leap years, which add an extra day roughly every four years. Over a full lifetime that adds up to many extra days, which is why this calculator counts actual calendar days instead.
- How do I calculate someone's age for a specific event, like retirement or a visa application?
- Set the second date to the relevant event date (for example, your planned retirement date or the date a form will be submitted) instead of leaving it at today's date, and the calculator will show the exact age on that day.