Something wrong with this tool?
About Batch Unix Timestamp Converter Online
This tool converts many Unix timestamps to readable date/time strings (or many dates back to Unix timestamps) in a single operation. Paste a list of timestamps — one per line — and the tool returns each one formatted as ISO 8601 in UTC and your local timezone.
Useful when analysing log files that record times as Unix epoch seconds or milliseconds, when bulk-processing exported database rows, or when reconciling timestamps across systems with different formats.
The tool auto-detects whether the input is seconds (10 digits) or milliseconds (13 digits), so you don't have to specify the unit. Mixed input is handled correctly line by line.
How to use this tool
How to convert many Unix timestamps to ISO at once
Paste the timestamps
Drop one timestamp per line into the "Timestamps (one per line)" field. The tool auto-detects seconds vs milliseconds — values with 13+ digits are treated as ms, shorter values as seconds.
Press Run
Result returns `lines` — an array of `<unix> -> <iso>` strings, in input order. Lines that don't parse as numbers are silently dropped, so check the count if you expect a specific length.
Output time zone
ISO output is always in UTC (suffix `Z`). For local time, post-process with `new Date(iso).toLocaleString(...)` or use a different tool that takes a target zone.
Where these come from
Common sources of batch timestamps: server logs (often seconds), JS `Date.now()` exports (always ms), database CSV dumps (depends on the schema). Mix is fine — the tool decides per line.