Log Timestamp Normalizer

Convert a column of mixed timestamp formats into one consistent timezone, with the assumed zone stated, DST ambiguity flagged and the original value kept.

Runs locally

Everything happens in your browser. What you paste or drop here is never uploaded, logged or stored.

Drop a CSV or a list of timestamps

One timestamp per line, or a CSV with a header row - you choose the column. Converted in your browser.

Or paste timestamps

Values without an offset were written in

Convert to

Year for syslog stamps (they have none)

Read 03/04/2026 as 3 April (day first) Input is CSV with a header row

One timeline needs one clock

Merging evidence from several systems means reconciling their clocks. One writes ISO 8601 with an offset, another writes Apache's 03/Mar/2026:10:00:00 +0000, syslog writes Mar 3 10:00:00 with no year or zone, and Windows exports carry FILETIME or /Date()/ values. This tool reads all of them. It also reads epoch seconds, milliseconds, microseconds and nanoseconds (told apart by their length), RFC 2822 mail dates, and US or European numeric dates. Each value is converted to UTC and to the zone you choose, and the original is kept beside it.

Assumptions are written down

A value with an offset is converted exactly. A value without one is read in the zone you select, and the result marks it as assumed. Where the source zone observes daylight saving, two cases are flagged rather than silently resolved:

wall-clock times that happened twice (the autumn overlap) - the earlier instant is used;
times that never happened (the spring gap) - the offset in force before the change is used.

Dates such as 03/04/2026 are flagged as day/month ambiguous. Sub-millisecond digits are marked as truncated.

Frequently asked questions

How is 1772532000 told apart from 1772532000000?

By length: 10 digits are seconds, 13 milliseconds, 16 microseconds, 19 nanoseconds, and 18-digit values in the right range are Windows FILETIME. Results outside 1900-2200 are rejected rather than shown as nonsense.

Where do the time-zone rules come from?

From your browser's built-in IANA time-zone database, the same one it uses for its own clock. No lookup is made over the network.

What happens to my CSV?

The export is your original rows with the normalised UTC and target-zone columns, the detected format and any note appended. Nothing is uploaded.

References

Related tools

What this tool can and cannot tell you. It reports what is present in the input you provide. It cannot see anything you did not give it, and a clean result means nothing was found in that input - not that the wider system is secure.

Security guidance here follows current published sources - OWASP, MDN, the relevant RFCs, NIST, CISA, FIRST and MITRE - which are linked beside the specific claims they support.