Timestamp Converter
Convert Unix timestamps and dates with timezone display.
Enter a valid timestamp to see conversions.
Values below 1,000,000,000,000 are interpreted as seconds; larger values as milliseconds.
Timestamp Converter translates Unix epoch values and human-readable dates in your browser. See UTC and local time, ISO output, relative phrasing, and automatic seconds-versus-milliseconds detection—powered by date-fns loaded only when you convert.
How it works
Choose Unix or ISO mode and enter a value. Numeric input below one trillion is treated as seconds; larger magnitudes as milliseconds. Parsed instants are formatted with date-fns for UTC, local timezone, ISO 8601, and a human-relative label.
Benefits
- Bidirectional Unix and ISO conversion
- Automatic seconds versus milliseconds detection
- UTC and local timezone display
- Clear errors for invalid input
- date-fns loaded dynamically to save bundle size
Use cases
- Decode API log timestamps during incident response
- Verify JWT exp claims or cache TTL values
- Convert database epoch columns for reports
- Check whether a payload uses seconds or milliseconds
Best practices
- Confirm unit detection when values sit near the threshold
- Prefer ISO 8601 with explicit offsets for ambiguous local times
- Use UTC when sharing timestamps across timezones
- Double-check negative epochs for pre-1970 historical dates
Common mistakes
- Treating millisecond values as seconds (off by 1000×)
- Forgetting daylight saving shifts in locale strings
- Pasting fractional Unix values without verifying truncation
- Assuming all APIs return the same epoch unit
Privacy
All timestamp parsing and formatting happen locally in your browser. ToolHub does not receive your values. Optional device history stores inputs only if you explicitly enable and save them on this machine.
Frequently asked questions
- Does the Timestamp Converter upload my values?
- No. Parsing and formatting run entirely in your browser using date-fns helpers loaded on demand.
- How does the tool detect seconds versus milliseconds?
- Numeric values at or above 1,000,000,000,000 are treated as milliseconds. Smaller absolute values are interpreted as seconds.
- Which timezones are shown?
- You always see UTC plus your browser local timezone. ISO 8601 output uses the Zulu suffix for the canonical instant.
- What date formats can I paste in ISO mode?
- ISO 8601 strings, locale date strings your browser understands, and common RFC-style timestamps via Date.parse.
- What happens with invalid timestamps?
- The tool shows a clear error message instead of silent wrong output—empty input, non-numeric Unix values, and unparseable dates are rejected.
- Can I insert the current time quickly?
- Yes. Use the Use now action to fill the input with the current Unix seconds or ISO string depending on the active mode.
- Is conversion history stored?
- Not by default. Optional on-device history can save recent inputs if you enable it on this browser profile.