Date calculators · Ages & date spans
Age Calculator
See an age on any date, with a readable calendar breakdown and the next birthday close at hand.
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Choose your dates.
Select your counting rules and calculate.
Calculation details
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How to use this calculator
Enter the birth date and the date to calculate age on. Calculate to see completed calendar years, months and remaining days, plus total days, whole weeks and the next birthday. Use the age-on field's Today button when needed.
Whole months are measured from the original day of month. If that day does not exist in the target month, its last day is used. For February 29, a year anniversary falls on February 28 in a common year. The age-on date cannot precede birth. Inputs are not saved unless you enable Remember this calculation.
A worked example
A birth date of February 29, 2000 reaches 25 calendar years on February 28, 2025 under this convention. On March 1, 2025 the result is 25 years and one day.
Does this calculate legal age or medical corrected age?
No. It is Gregorian calendar arithmetic, not a jurisdiction-specific legal age, traditional cultural age or medical assessment. A copied setup link contains the birth date, so share it only when you intend to disclose that information.
Which calendar and years are supported?
These tools use Gregorian calendar dates for years 1–9999, without historical calendar-switch dates. They count dates, not elapsed hours. Today buttons use the current date in your browser's time zone.
What happens to my dates?
Calculations run on your device. Saving a calculation is optional and keeps it in this browser. A setup link contains the dates and settings you entered; anyone with the link can read them. Use one tab per saved calculator. Clear saved data from Privacy & settings.