Date & time · Unix epoch
Days since the epoch.
Count the days between 1 January 1970 and any date, or turn a day count back into a calendar date. Days are whole UTC calendar days, the way epoch-day fields in databases and file formats count them.
Convert
Result
Choose a date or enter a day count.
How the day count works
Day 0 is 1970-01-01. Each UTC calendar day adds 1, so 1970-01-02 is day 1 and 1969-12-31 is day -1. Because Unix time counts every day as exactly 86,400 seconds, days since the epoch is simply Unix seconds divided by 86,400, rounded down. Today's count is at the top of the page.
Where you meet it
Epoch-day counts appear as date columns in analytics and columnar file formats, in java.time.LocalDate.toEpochDay(), and in spreadsheet and data-warehouse exports. Excel is different: its serial numbers count from 1900 or 1904, see Excel date to Unix.
| Day count | UTC date |
|---|---|
0 | 1970-01-01 |
1 | 1970-01-02 |
-1 | 1969-12-31 |
365 | 1971-01-01 |
10000 | 1997-05-19 |
20000 | 2024-10-04 |
FAQ
How many days since 1 January 1970?
The counter at the top of this page shows the whole days elapsed to the current UTC date.
How do I convert days since epoch to a date?
Switch to Days since epoch to date, enter the count, and read the UTC date. Negative counts give dates before 1970.
How is days since epoch related to the Unix timestamp?
Days = floor(Unix seconds / 86400). It works cleanly because POSIX defines every day as exactly 86,400 seconds.
Does Unix time include leap seconds?
No. POSIX counts each day as exactly 86,400 seconds, so a leap second is not a separate value: the timestamp repeats or is smeared by the system clock, and 2017-01-01T00:00:00Z is 1483228800 even though UTC itself had a leap second added at the end of 2016. IERS Bulletin C 72 (July 2026) announced that no leap second will be introduced at the end of December 2026.
Can a Unix timestamp be negative?
Yes. A negative value is a moment before 1970-01-01, for example -1 is 1969-12-31T23:59:59Z. POSIX leaves the formula undefined before 1970, but most languages extend the same arithmetic backwards and so does this tool.
What is the largest date this converter accepts?
JavaScript time values run from -8,640,000,000,000,000 to 8,640,000,000,000,000 milliseconds around the epoch, about 275,000 years either side of 1970. Values outside that range are rejected rather than guessed.
Is my data sent anywhere?
No. The conversion runs in your browser and nothing you type is uploaded or stored.
Sources (each opened 2026-10): POSIX.1-2017 Base Definitions, 4.16 Seconds Since the Epoch; ECMAScript Language Specification, Time Values and Time Range; IERS Bulletin C 72 (leap second announcement, July 2026).