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Chrome and other WebKit-based browsers store history, cookies, and cache timestamps as microseconds since January 1, 1601 — the same reference date as Windows FILETIME, but a different unit. Decode one below.
Found in Chrome's History and Cookies SQLite databases (columns like last_visit_time or creation_utc).
Because Chrome's SQLite databases store these as plain integers with no unit label, browser-history analysis tools and incident responders need to know the convention on sight: typically 17 digits, microseconds, since 1601. It's easy to confuse with Unix microseconds (16 digits, since 1970) at a glance — the extra digit and the very different leading digits are the tell.
Firefox's places.sqlite uses plain Unix microseconds (since 1970), and Safari's WebKit history uses Mac Absolute Time (seconds since 2001) — see the Mac Absolute Time Converter for that one. Three major browsers, three different timestamp conventions, in files that otherwise look identical at a glance.
Related
The same 1601 epoch, at 100-nanosecond resolution instead of microseconds.
Safari's timestamp convention — seconds since 2001.
Pull timestamps out of messy log or export text automatically.