WebKit / Chrome Timestamp Converter
Convert Chrome/WebKit timestamps (microseconds since 1601) from cookies and history databases.
WebKit Time ⇄ Timestamp
Runs entirely in your browserType in either field — the other updates live.
Uses BigInt internally — regular JavaScript numbers lose precision above 253, which WebKit timestamp values exceed today.
What is a WebKit Timestamp?
A WebKit timestamp counts microseconds since January 1, 1601, 00:00:00 UTC — the same epoch as Windows FileTime, but measured in microseconds instead of 100-nanosecond intervals.
It's the format Chrome (and other Chromium/WebKit-based browsers) use internally for cookie expiry and browsing history timestamps in their SQLite databases.
- Microseconds since January 1, 1601 UTC
- Used in Chrome's
CookiesandHistorySQLite databases - Same epoch as Windows FileTime, different unit (µs vs 100ns)
- Offset from Unix epoch: 11,644,473,600,000,000 microseconds
WebKit Timestamp Format
Subtract 11,644,473,600,000,000 and divide by 1,000 to get Unix milliseconds.
How do I convert a Chrome cookie timestamp to a date?
Paste the raw integer from Chrome's Cookies or History database into the converter above. It subtracts the WebKit-to-Unix epoch offset and converts to a readable date, using BigInt math to stay precise.
Frequently Asked Questions
Cookies database's expires_utc column and the History database's last_visit_time column both store raw WebKit timestamps.
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