This works out an exact age in years, months, and days from a birth date, along with total days lived. It handles the fiddly parts, varying month lengths and leap years, automatically, so you get a precise answer instead of a rough guess.
How to use it
- Select or type a date of birth.
- Read the calculated age in years, months, and days right below.
- Check the total days lived figure for a single combined number.
- Change the date to check a different birth date.
- Use the result for a form, a milestone, or plain curiosity.
When it helps
- Filling out an official form that asks for exact age, not just years.
- Planning a milestone, like a ten thousandth day celebration, using the total days figure.
- Checking eligibility for something with a precise age cutoff.
- Satisfying curiosity about exactly how many days old you are.
- Working out a pet's or an object's age using its own start date.
Good to know
- The calculation accounts for leap years automatically, so it stays accurate even for a February 29 birth date.
- Age in months and days looks a little different depending on today's date, since months have different lengths.
- For legal or medical purposes, check your context's exact rules, since some places define age slightly differently.
- If you're calculating age for an eligibility requirement with a specific cutoff date, check whether the rule uses that exact date rather than today, and adjust accordingly.
- If you're double checking someone's eligibility for something age restricted, calculate as of the specific date the rule cares about, not necessarily today.
Why dates can differ
Different systems count age differently. Some cultures count a baby as one year old at birth, and legal ages can depend on the local rules. This tool uses the standard method of completed years.
Questions
Why do months and days sometimes come out larger or smaller than I expected?
Because months have different numbers of days, the exact breakdown depends on which specific months fall between the birth date and today.
Does this account for leap years correctly?
Yes, it's based on real calendar dates, which naturally accounts for a leap year's extra day in February.
Can I use this for something other than a person?
Yes, any date works the same way, whether it's a birth date, an adoption date, or a manufacture date.
Can I calculate age as of a future or past date rather than today?
This compares the birth date to today automatically. Checking age as of a different reference date would need a manual adjustment or the date difference tool instead.
Why do different age calculators sometimes disagree slightly?
Small differences usually come from how each tool handles an edge case, like someone born on the 31st in a month the current comparison month doesn't have.
Does this handle someone born before a certain historical calendar change?
This assumes the standard modern calendar throughout, which covers essentially every practical use case for calculating a person's age today.