Convert Seconds & Days Since Year 0-1970

On this page we have some variants of the Unix epoch:

Convert seconds Since Year 0

This tool converts seconds since year 0 to human-readable dates.
It's compatible with MySQL's TO_SECONDS function (MySQL 5.5+).
Year 0 is defined as 0000-00-00 00:00 GMT. Please note that this is not a valid date! There is no year 0.

At this time there are ~63869259750 seconds since year 0 (6.386E10).
Visit the homepage to convert to/from seconds since 1/1/1970.

Convert seconds to normal date:


Convert seconds Since 0001-01-01 AD

This tool converts seconds since January 1, 1 AD (extrapolated Gregorian calendar) to regular dates.
There were ~63837637350 seconds since Jan, 1 0001 (6.383E10).


Convert days Since Year 0

Compatible with MySQL's TO_DAYS function (MySQL 5.5+).

There are 739227 days between 0000-00-00 and today (Friday, Dec 8, 2023).

Convert days to normal date:


Convert days Since 0001-01-01 AD

There were 738861 days since January 1, 1 AD.


Convert days Since 1900-01-01

There were 45266 days since January 1, 1900.

This number (+2) is used in the Microsoft Excel date functions such as DAY(serial_number) and WEEKDAY() .

Note, Excel's serial number is 2 higher than the number on this page.

  • In Excel January 1 is serial number 1. In this converter midnight January 1, 1900 is 0, after 1 day it is midnight on January 2. To correct this you have to add/subtract 1.
  • Excel incorrectly sees 1900 as a leap year (for compatibility with Lotus 1-2-3) so you have to add/subtract 1 to all days when using in Excel. Also see: Excel incorrectly assumes that the year 1900 is a leap year


Convert days Since 1904-01-01

There were 43806 days since January 1, 1904h.

This number (+1) was used for Microsoft Excel date functions on earlier versions only for the Mac.
Excel 2016 for the Mac uses 1900 as a default start date.


Convert days Since 1970-01-01

There were 19699 days since January 1, 1970, the Unix epoch.


Please note: This page might be cached, the current day uses GMT/UTC time.
This page uses JavaScript to convert times & dates. This may not work properly in all browsers.