Format Timestamps in TSV Files Online
Reformat timestamp and date columns in TSV files directly in your browser. Convert between ISO 8601, Unix epoch, US date, and custom strftime patterns — no upload required.
How to format Timestamps in TSV files
- Drop your file onto the upload area. The first 200 rows are shown, and the first date or timestamp column is pre-selected if the file has one.
- Pick the column to format. The dropdown shows each column's detected type, and the output column name defaults to the column name plus _formatted.
- Choose the input format: Auto-detect for ISO-style text, Unix epoch in seconds or milliseconds, or a custom strptime pattern such as %d/%m/%Y.
- Choose the output format: ISO 8601, date only, US date, Unix epoch seconds or milliseconds, or a custom strftime pattern. Then click Format Timestamps.
- Check the result preview and download the file. The formatted column replaces the original in the same position.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
A set of temperature sensors logs readings with slightly different timestamp styles, and one device writes "n/a" when its clock has not synced. A US reporting template needs plain MM/DD/YYYY dates.
Input (TSV)
sensor_id event_time temp_c
S-01 2026-04-11 08:15:32 18.4
S-02 2026-04-11T23:59:59 17.9
S-01 2026-04-12 00:00:05 18.1
S-03 n/a 19.2Settings
- Column to format: event_time (VARCHAR)
- Output column name: event_time_formatted (default)
- Input format: Auto-detect
- Output format: US date (01/15/2024)
Result
| sensor_id | event_time_formatted | temp_c |
|---|---|---|
| S-01 | 04/11/2026 | 18.4 |
| S-02 | 04/11/2026 | 17.9 |
| S-01 | 04/12/2026 | 18.1 |
| S-03 | NULL | 19.2 |
Auto-detect reads both the space and the T separator as timestamps. The US date output keeps only month, day and year. "n/a" cannot be read as a time, so it becomes empty rather than stopping the run. The original event_time column is replaced by event_time_formatted in the same position, so keep a copy if you need both.
Frequently Asked Questions
What happens to values that cannot be read as a timestamp?
With Auto-detect they become empty (NULL) and the rest of the column is converted. With a custom strptime pattern, any value that does not fit the pattern stops the run with an error, so the file is not half converted.
Does the tool keep the original column?
No. The formatted column replaces the original in the same position, under the output column name you set. Keep your original file if you need both versions.
Which time zone are the results in?
UTC, whatever time zone your computer uses. Epoch seconds and epoch milliseconds are both read as UTC. In Auto-detect, a value with an offset or Z, such as 2026-04-11T08:15:32+02:00, is converted to UTC. A value without an offset is kept exactly as written.
Is there a European DD/MM/YYYY output option?
Not as a preset. Choose Custom pattern (strftime) as the output and enter %d/%m/%Y. The same field takes any strftime tokens, such as %d %b %Y for 11 Apr 2026.
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