Date/Time Calculator

Calculate the time since or until a specified date, the time difference between two dates or times, or add or subtract a time interval.

What is the Date/Time Calculator?

Our Date/Time Calculator is a free online tool that calculates dates and date intervals and allows:

To explore the date/time properties - how many weeks, days, and hours passed since the date/time or how much time is left until it.
To calculate the time difference between two dates.
To add or subtract a time interval to a given date/time.

Any real-world examples?

How to use

To calculate the difference between two dates and/or times of day, enter a date and/or time into the fields above in almost any conventional date/time format.

The default time zone is UTC (Universal Coordinated Time, GMT).

This calculator can be used to add or subtract two time values. The first date can be left blank, which will be taken as "Now" by default. In the second field, you can enter any date, time, or interval addition or subtraction, for example, "+180 days", "-6 month", "+38 weeks", "36 hours", etc.

Usage cases

There are some usage cases our calculator is useful for:

You know the start date and need to count how many days have passed since you received the bill or letter.
You want to calculate the end date of the validity of your vaccination certificate, prescription, etc. For example, you can easily calculate the expiration date of your EU Digital COVID Certificate adding the validity period of 270 days to your date of vaccination.
You know the date of your departure and want to know that is the last date to buy tickets at the early bird price.
You know the date of purchase and want to know how long the electric bulb/your phone/any other product lasted.

What datetime formats are supported?

The calculator can handle almost any date/time format, including:

4/26/1986
March 1 1994
July 30, 2020 4:50
15 March 2022
20180817203005000
20210126
2022-03-15
2022-03-15 10:55
2022-03-15 10:55 pm
2022-03-15 10:55 pm UTC
2022-03-15 10:55 pm PST
First Sunday of May
@1215282385 (prepend number with @ to be interpreted as a Unix Timestamp)
…