Age Calculator
Calculate an exact age from a birth date, or the number of days between any two dates.
Runs entirely in your browser, nothing is uploadedCalculate an age or date span in three steps
- Choose age from birth date, or days between two dates.
- Pick the date or dates using the date pickers, defaults to today where useful.
- Read the exact breakdown in years, months, weeks, and days, updated as you change either date.
Why people use the Age Calculator
Everything worth knowing before you dive in.
How it helps
Working out an exact age or the span between two dates by hand means accounting for different month lengths and leap years, easy to get slightly wrong. This tool calculates both directly from calendar data, giving a precise breakdown down to the day rather than a rounded estimate.
Built for real use
The age mode shows years, months, and days since a birth date, along with total days lived and time until the next birthday, useful for forms, certificates, or just curiosity. The days between mode takes any two dates and returns the exact span in days, weeks, and months, handy for calculating a deadline, a notice period, or how long an event lasted.
Private by default
Both calculations run instantly in the browser as soon as valid dates are selected, with no need to count on a calendar or use a spreadsheet formula.
Pro tip
When checking eligibility for something with a strict age cutoff, use the as of date field to see the exact age on that specific date rather than today, which avoids off by one errors around a birthday.
Common questions
Does the age calculation account for leap years?
Yes, the calculation is based on actual calendar dates, so leap years are handled correctly without any manual adjustment.
Can I calculate age as of a date other than today?
Yes, the as of date field defaults to today but can be set to any date, useful for calculating someone's age at a specific past or future event.
What's the difference between the two modes?
Age from birth date is built specifically for calculating someone's age, while days between two dates works for any pair of dates, not just birthdays.