Age & Date Calculator
Find your exact age, count days between dates, or add days to any date — three tools in one.
Date of Birth
Age
36 yrs
4 mo 15 d
Total days
13,284
1,897 weeks
Total hours
318,816
Next birthday
230 days
About this tool
A three-in-one date calculator: compute your exact age in years/months/days (with next-birthday countdown), find the difference between any two dates in days/weeks/hours/minutes, and do deadline math by adding or subtracting any number of days from a date.
How to use it
Quick steps to get the most out of this utility.
- 1
Choose a mode
Age Calculator, Date Difference, or Add / Subtract Days.
- 2
Enter your dates
Pick dates with the date pickers — no manual typing required.
- 3
Read the results
Years, months, days, total days, weeks, hours, and minutes all calculated at once.
Common date calculation scenarios
- Legal and medical age: precise age as of a specific hearing or appointment date
- Project deadlines: 30, 60, or 90 business-day calculations
- Subscription renewals: how many days until a contract expires
- Historical research: how long ago a historical event occurred
- Retirement planning: how many days until a target date
Frequently asked questions
How is age calculated exactly?+
Age is computed by subtracting the birth date from the reference date in years, months, and remaining days. For example, if you were born on March 15, 1990 and today is January 10, 2025, you are 34 years, 9 months, and 26 days old.
Can I calculate age at a past or future date?+
Yes. Set the "As of date" field to any date — past or future — to see how old someone will be or was at that point.
How many days between two dates?+
Use the Date Difference mode. It counts the total number of days (and converts to weeks, hours, and minutes) between any two dates you choose.
What does adding days to a date mean?+
The Add / Subtract Days mode takes a start date and a number of days, then tells you the resulting date. Useful for deadline math: "30 days from today" or "45 days before an event."
Does the calculator handle leap years?+
Yes. JavaScript's Date object correctly accounts for leap years, so February 29 birthdays and calculations spanning leap years are handled accurately.
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