Date and time
Convert Chrome database microseconds to UTC dates, or enter ISO dates with an explicit offset. One value per line.
Your input is processed in this browser and is not sent to a server.
Chrome database epoch: 1601-01-01 UTC · one unit = one microsecond.
One signed decimal integer per line, or YYYY-MM-DDTHH:mm:ss[.1–6 digits]Z / ±HH:mm. Dates must resolve to UTC years 0001–9999.
Zero has an arithmetic date but may mean unset in Chromium. Signed 64-bit minimum/maximum values are infinity sentinels, without dates.
UTC shows six fractional digits. Unix seconds and milliseconds are floored, with nonnegative microsecond remainders.
Up to 1,000 physical lines and 100,000 UTF-16 code units. Blank rows are errors; outer whitespace is trimmed.
Reverse is available only when every row has a date. Errors and infinity sentinels must be resolved first.
Enter input or choose an example to begin.
Use the WebKit timestamp converter when a Chrome history export contains long integers instead of readable dates. Start with the original database value: a spreadsheet may already have rounded the final digits before you paste them here.
The familiar WebKit name refers here to the Chrome/Chromium format measured from 1601. A browser API can use a different epoch or unit even when its field has a similar name. Check the source before interpreting the result.
The WebKit timestamp converter turns 11644473600000001 into 1970-01-01T00:00:00.000001Z. Reversing the result preserves that last digit. Six fractional places remain visible even when your usual date viewer stops at milliseconds.
A malformed entry does not cancel its neighbors. The batch report retains the original text and physical line number, so you can match each converted date or error to its source rather than realigning a shortened list.
Chrome history timestamp fields such as visits.visit_time use this format. The extension API’s lastVisitTime uses Unix milliseconds. A short integer is not rejected just for being short, so digit count cannot replace checking the source.
For the reverse direction, include Z or ±HH:mm even when your own computer uses UTC. The Example button follows the selected direction and previews its replacement before Apply. Fractions longer than six digits are rejected rather than truncated.
Automatic conversion waits 350 ms; switch it off for Convert or Ctrl/Cmd+Enter. Editing immediately disables exports until the result refreshes. Reverse requires all rows to have dates, and Undo restores both the input and the earlier report.
The Chrome timestamp converter keeps large counters as integer strings in JSON. A current microsecond value exceeds JavaScript’s safe integer limit; converting it to a floating-point number before subtraction could lose an odd final digit.
WebKit to Unix conversion first subtracts 11644473600000000 microseconds. The report includes exact Unix microseconds as well as floored seconds and milliseconds. The leftover microseconds are separate fields, so coarse units can be reconstructed without guessing.
Negative WebKit values represent dates before 1601 within the supported calendar range. One microsecond before 1970 gives Unix seconds -1 plus a remainder of 999999 microseconds, not a misleading zero-second quotient.
Each batch accepts up to 1,000 physical lines and 100,000 UTF-16 units. Results initially show 50 rows, with 50 more per click. Copy and Download include every row, original input, interpretation and error message in the JSON report.
For an original creation_utc or expires_utc counter in this format, paste the decimal integer in WebKit → date mode. Read the UTC date and retain the field name separately. A zero or special value needs the cookie record’s context before you infer creation or expiry.
They share 1601-01-01 UTC as the epoch, but their units differ: one microsecond here versus 100 nanoseconds for FILETIME. A normal FILETIME count is ten times the corresponding Chrome count. Use the matching converter rather than swapping the values.
Chromium uses zero for an uninitialized time. Arithmetic conversion still lands on 1601-01-01, so this page shows both that result and a possibleNull notice. It cannot determine whether a cookie is a session cookie or a history field is unset from the number alone.
Enter a current ISO date with Z or an explicit offset in Date → WebKit mode. The formula is Unix microseconds + 11644473600000000. This page does not sample the clock for you; a source recorded only to milliseconds cannot supply three extra measured digits.
Copy a value from the original visits.visit_time or urls.last_visit_time column and read the UTC result. To reconcile a local display, account for its time zone. Do not apply this conversion to the extension API’s similarly named lastVisitTime, which uses milliseconds from 1970.
Unexpected result?
Return to the WebKit timestamp converter with a source value you can verify. Inspect its UTC date, special-value notice and Unix remainder, then save the complete report.