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Confirm the source unit
Use seconds for a seconds-based API or the JavaScript/Java preset for milliseconds. Detection proposes a unit for one 10-, 13-, 16- or 19-digit number; it waits for your confirmation.
Date and time
Unix timestamp converterRead the instant, keep the precision
Convert one value or a batch using explicit units and a named timezone.
Unix timestamp converter
Input
Your input is processed in this browser and is not sent to a server.
Results
Options
One decimal integer or strict date with seconds per line. Choose the timestamp unit. Dates may include Z or a numeric offset; otherwise the selected timezone is used. The report highlights the selected unit value and its nanosecond remainder while retaining all four units.
A suggestion for one 10-, 13-, 16- or 19-digit integer only. Confirm the source unit before applying; detection never changes it automatically.
Coarser units round toward negative infinity and flag a remainder. Now uses a millisecond device-clock snapshot; extra digits do not add clock precision.
Unzoned times that are missing or repeated at a clock change are rejected. An explicit offset determines the instant; the selected zone controls display.
Reverse requires fresh results with no errors. It uses UTC dates in one direction and nanosecond integers in the other to preserve precision.
Up to 1,000 physical lines and 100,000 UTF-16 code units. Empty lines are reported as errors.
Enter input or choose an example to begin.
A Unix timestamp converter helps when a JavaScript event, a server log and a tracing export represent the same instant with different numbers. Select the source unit before comparing the results.
This epoch converter keeps integer nanoseconds intact. A date without an offset needs a timezone; a date ending in Z or a numeric offset already identifies an instant.
Why use this Unix timestamp converter?
Keep the digits that matter
The Unix timestamp converter preserves microsecond and nanosecond input instead of passing a large integer through floating-point arithmetic. Compare coarse values with the remainder markers before copying them.
Compare zones without changing the instant
An overnight log can show different calendar dates in UTC and your selected zone. Both displays refer to one instant, so a timezone change does not alter the underlying timestamp.
Check units, offsets and the complete report
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Resolve local time explicitly
Enter an IANA zone such as Europe/Berlin when a date has no offset. At a repeated or missing daylight-saving hour, supply an explicit offset to identify an instant.
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Review before replacing input
Automatic conversion refreshes after edits; turn it off to run manually. Example, Clear, Now and Reverse show a replacement preview. Reverse needs fresh, entirely successful results; Undo restores the previous input and output.
Exact values in both directions
Four integer units
Convert timestamp to date using seconds, milliseconds, microseconds or nanoseconds. Results retain all four unit values and the UTC instant.
Chosen timezone
Read the selected zone beside UTC. Date to timestamp interprets unzoned input in that zone; a supplied offset takes precedence.
Batch diagnostics
One value per physical line, with line and column positions for failures. Blank lines remain errors so an incomplete batch cannot look complete.
Complete report export
Copy or download the report with every row, including rows beyond the visible preview. Changed input or options disable export until the report is refreshed.
Precision and parsing boundaries
- Strict date syntax
- Use YYYY-MM-DDTHH:mm:ss or one space instead of T, with optional 1–9 fractional digits and Z, ±HH:mm or ±HH:mm:ss. Four-digit years or signed six-digit years are accepted; -000000 is invalid. Date-only text, leap seconds, 24:00 and unknown -00:00 offsets are rejected.
- Integer timestamps
- Use a decimal integer in the selected unit. No scientific notation, decimal fractions, separators or automatic unit changes. The instant must be within ±8640000000000000000000 nanoseconds of the Unix epoch.
- Floor and remainder
- Milliseconds to seconds and other coarser conversions round toward negative infinity. For example, -1 nanosecond gives -1 second with a remainder; the nanosecond value still preserves the exact instant.
- Timezone ambiguity
- Without an offset, missing or repeated local times are rejected. An explicit offset determines the instant even when it differs from the selected zone; the zone then controls display. Historical rules depend on browser timezone data.
- Batch limits
- At most 1,000 physical lines and 100,000 UTF-16 code units. Oversize input is rejected as a whole. No file upload, spreadsheet date serials, natural-language dates or date arithmetic.
- Snapshot and reversal
- Now captures the device clock in milliseconds; extra output digits do not add clock precision. Reverse uses UTC dates from timestamp results and nanoseconds from date results to avoid losing fractional precision.
Unix timestamp converter questions
How do I convert a timestamp to a date?
Select timestamp to date, choose the unit used by the source system and enter the integer. The report shows UTC and your chosen timezone. For a batch, use one integer per line.
Why does my timestamp have 13 digits?
For contemporary dates, 13 digits usually means milliseconds and 10 usually means seconds. Digit count is a clue, not a guarantee; confirm the unit against the producer’s documentation.
Are timestamps timezone-aware?
The number identifies an instant relative to the UTC epoch and stores no regional timezone. A timezone is needed only to display it or interpret a local date without an offset.
Can Unix timestamps be negative?
Yes. Negative values describe instants before 1970-01-01T00:00:00Z. Coarser outputs use floor division, so a tiny negative fraction does not incorrectly become zero.
How do I handle Daylight Saving Time with timestamps?
Regional display follows IANA timezone rules. For reverse conversion, an unzoned local time that occurs twice or does not exist is rejected; provide a numeric offset to disambiguate.
Unexpected result?
Use the Unix timestamp converter
Check a known instant with the Unix timestamp converter, then export a complete report with its chosen unit and timezone.