On this page some variants of the Unix epoch:

- Seconds since year 0 (MySQL compatible)
- Seconds since January 1, 1 AD
- Days since year 0 (MySQL compatible)
- Days since January 1, 1 AD
- Days since January 1, 1900, used for Excel DAY functions
- Days since January 1, 1904, formerly used for Excel DAY (Macintosh)
- Days since January 1, 1970, Unix epoch

## 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 ~**63782383221** seconds since year 0 (6.378*10^{10}).

Visit the homepage to convert to/from seconds since 1/1/1970.

Convert seconds to normal date:

## Seconds Since 0001-01-01 AD

This tool converts seconds since January 1, 1 AD (extrapolated Gregorian calendar) to regular dates.

There were ~**63750760821** seconds since Jan, 1 0001 (6.375*10^{10}).

## Days Since Year 0

Compatible with MySQL's `TO_DAYS`

function (MySQL 5.5+).

There are **738222** days between 0000-00-00 and today (Sunday, Mar 07, 2021).

Convert days to normal date:

## Days Since 0001-01-01 AD

There were **737856** days since January 1, 1 AD.

## Days Since 1900-01-01

There were **44261** 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

## Days Since 1904-01-01

There were **42801** 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.

## Days Since 1970-01-01

There were **18694** 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.