Time & Date Tools
More Tools
Time and Date Calculators
These tools handle the everyday date arithmetic that is surprisingly awkward to do by hand — counting days between dates, figuring out how long until an event, calculating someone's exact age, or adding time intervals together.
Days Between Two Dates
The days-between calculator counts the exact number of days separating two calendar dates. Useful for project timelines, contract durations, deadline calculations, and historical date research.
The result can be expressed as total days, or broken down into years, months, and days for a more human-readable interval.
Days Until a Date
Counts down the number of days remaining until a specific date — a deadline, birthday, holiday, event, or personal milestone. The calculation updates based on today's date each time you open the page.
Age Calculator
The age calculator computes a person's exact age in years, months, and days as of today's date (or any comparison date you specify). Useful for legal and administrative contexts where an exact age in days matters, and for anniversary and milestone tracking.
Time Addition Calculator
Adds time intervals (hours, minutes, seconds) together — useful for calculating the total running time of a playlist, the cumulative hours on a timesheet, or the total length of a series of videos or tracks.
Unlike regular addition, time carries at 60 (60 seconds = 1 minute, 60 minutes = 1 hour), which makes manual calculation error-prone. The calculator handles the carries automatically.
Date Arithmetic Reference
A few useful facts about date calculations:
- A regular year has 365 days; a leap year has 366.
- Leap years occur in years divisible by 4, except century years (divisible by 100) which are only leap years if also divisible by 400. So 2000 was a leap year; 1900 was not.
- Months have 28–31 days, which is why "1 month" is not a fixed number of days.
- An exact day count is always unambiguous; "months and years" involves interpretation of partial months.
Frequently Asked Questions
How do I calculate my exact age in days?
Use the age calculator and select the option to show the result in days, or use the days-between calculator with your date of birth and today's date.
Does the days-between calculator include both the start and end dates?
By default the calculation counts the number of days separating the two dates, not including one or both endpoints. If you need to include both ends (as in "the event runs Monday through Friday inclusive"), add 1 to the result.
How many days until Christmas/New Year/my birthday?
Use the days-until calculator, enter your target date, and it will display the count from today automatically.