Date to Millisecond Calculators

Several date to millisecond calculators, useful when coding countdown timers, cookie expiration settings or other date related scripts. The calculators are coded in JavaScript.

If you need to do date math across timezones, follow this link to a couple date/timezone tools at the bottom of this page.

The Current Millis:

Your computer's time:

-- the start of Unix Epoch Time
in your time zone ( ).

Convert a millisecond value to a date string

this (milli ) second time number:

is the equivalent in time zone:

to this date string:

Date to milliseconds converter
What date would that be?

Your computer's time:

equals this date:

A temporal value converted to milliseconds

equals so many (milli ) seconds:

Milliseconds converted to a temporal value

So many (milli ) seconds: equals so many

How much time between now and then?
Your computer's time:
are so many apart:
How much time between now and then (using a millisecond date value)?

Your computer's time:

and this date in (milli ) seconds:

are so many apart:

Date and Time Math Across Timezones

Date and Time Plus/Minus Quantity of Time
in timezone
so many
equals this date and time in this timezone
Date/Time Subtraction
in timezone
in timezone
equals so many


  1. Good, but not satisfying all the needs. Is there an other tool like this which can be used for all the types in calendar and gregorian calendar or date.

  2. Let my input date is “01/01/2009” in MM/DD/YYYY format. How I will calculate in java script that the input date is not before “09/30/2009” and not after “03/31/2011”. Please sent me the Java script code to my E-Mail. Thanks

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  4. Milliseconds to date string different than date to milliseconds for the same date:

    1392126870991 results in Tue Feb 11 2014 14:54:30 GMT+0100 (W. Europe Standard Time), while

    Tue Feb 11 2014 14:54:30 GMT+0100 (W. Europe Standard Time) gives 1392126870000.

    Is there a way to ensure that Tue Feb 11 2014 14:54:30 GMT+0100 (W. Europe Standard Time) gives also 1392126870991?

    Thanks in advance.

    • Thanks for pointing this out. I guess there may be a bug in my code that converts Tue Feb 11 2014 14:54:30 GMT+0100 to milliseconds. might not respect the timezone portion.

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