Chrome / WebKit Timestamp Converter

How to use

1. 1Pick the format: Chrome / Chromium for microseconds since 1601 (used in Chrome SQLite databases and the Bookmarks JSON file) or WebKit NSDate for seconds since 2001 (used by Safari WebKit, NSDate, and CFAbsoluteTime).
2. 2Pick the direction: Timestamp to date to decode a numeric value, or Date to timestamp to encode a calendar date you choose.
3. 3In decode mode, paste the timestamp. Chrome values accept decimal, 0x-prefixed hex, and _ , space digit separators. NSDate values accept decimal seconds or scientific notation; negative values are valid.
4. 4In encode mode, pick a date and time with the local picker. The output shows the matching Chrome microseconds (and the equivalent FILETIME) or the matching NSDate seconds, plus the input restated in UTC and ISO 8601.
5. 5Use the Use now button to fill the current moment, tap a preset to load a worked example, or copy any individual value or the full summary with the Copy buttons.

About this tool

Chrome / WebKit Timestamp Converter decodes the two timestamp formats that web searches lump together as 'webkit timestamp' and converts both directions. The first is the Chrome / Chromium / Edge format: a 64-bit integer counting microseconds since January 1, 1601 at 00:00:00 UTC. It is the value stored in history.sqlite (visit_time, last_visit_time), Cookies (expires_utc, last_access_utc), Login Data (date_created, date_last_used), Top Sites, and the date_added and date_modified fields inside the Bookmarks JSON file. Because these values routinely exceed 2^53, every Chrome calculation uses BigInt so the full microsecond precision is preserved through both decoding and encoding. The second is the Apple NSDate / CFAbsoluteTime format: floating point seconds since January 1, 2001 at 00:00:00 UTC, used by Safari WebKit, Cocoa NSDate fields, binary plists, and many macOS and iOS app exports. Negative NSDate values are valid and represent dates before 2001. Inputs accept decimal numbers, hexadecimal (for Chrome values, 0x-prefixed), and digit separators such as underscores, commas, or spaces. The decode panel returns the UTC date, the ISO 8601 string with full available precision, a localized time in your browser zone, a Unix seconds and milliseconds value, a human-readable relative time, and the original timestamp restated in decimal, hex, and microsecond grouping. The encode panel takes a date from a local time picker and produces the matching Chrome microseconds (and the equivalent Windows FILETIME, exactly ten times the Chrome value) or the matching NSDate seconds. Presets cover a sample Chrome visit_time, the Chrome zero (the 1601 epoch), a typical NSDate, the NSDate zero (the 2001 reference date), and a pre-2001 negative NSDate. Nothing is uploaded; the timestamps in your input never leave your browser.

Free to use. Works in your browser. No signup, no login.