Is the value I enter sent anywhere?

No. The conversion and the time zone calculation run on your device with your browser's built-in functions; the value you type is not sent over the network or stored.

Why does the tool take it for milliseconds instead of seconds (or the other way round)?

The unit is guessed only from the size of the number: 10-digit numbers are seconds, 13-digit numbers milliseconds, and so on. If the date is far from what you expected, choose the unit manually under "Unit of the number"; the tool also lists the reading in each unit.

What is the Year 2038 problem?

Systems that keep seconds in a signed 32-bit integer overflow at 2038-01-19 03:14:07 UTC (2³¹−1 seconds) and the counter turns negative. Modern systems use 64 bits; old embedded devices, 32-bit database fields and some file formats are at risk. The tool flags values beyond this limit.

Why is a local time "ambiguous" or "never happens"?

When daylight saving starts, clocks are put forward (e.g. 02:00 → 03:00) and the local times in between never happen. When it ends, clocks are put back (03:00 → 02:00) and the local times in between happen twice. In both cases converting from the local time alone to an instant is not unique; use an offset or UTC.

What is the difference between a UTC offset and an IANA time zone?

An offset (+03:00) is the difference at that moment. An IANA zone (Europe/Berlin) is the name of the offset and daylight saving rules as they change over time. For a past instant an offset is enough; to store a future local appointment you also need the zone name, because the rules can change.

Does Unix time count leap seconds?

No. In Unix time every day has exactly 86,400 seconds; a leap second takes the same value as the previous second or repeats it. This tool also reads second 60 as the start of the next minute.

Timestamp and time zone converter

Paste a timestamp or a date: Unix seconds, ms, µs, ns, ISO 8601, RFC 2822 and local text appear in all formats and in the time zones you choose (with the UTC offset). Local times that do not exist or occur twice at a daylight saving change are flagged. The conversion runs in your browser; nothing is sent.

Free tool · Integration

Timestamp or date

A number (Unix), ISO 8601 (2026-10-06T14:30:00+03:00), RFC 2822 (Tue, 06 Oct 2026 14:30:00 +0300) or 06.10.2026 14:30. Dates without an offset are interpreted in the input time zone below.

Input time zone

Dates without an offset (2026-10-06 14:30) are taken as wall-clock time in this zone.

Current time from your browser clock: …

Examples:

The conversion runs in your browser; the value you type is not sent anywhere or stored.

Add a time zone (IANA name)

Common mistakes

An offset is not a time zone: +03:00 is only a difference, while Europe/Istanbul carries all past and future rules. When storing a future appointment keep both the UTC instant and the IANA zone name.
At a daylight saving change a local time either never happens (e.g. 02:30 on the last Sunday of March in Germany) or happens twice; converting a local time to an instant is then ambiguous. Between systems carry the instant in UTC or as ISO 8601 with an offset.
The 2038 limit: a signed 32-bit seconds counter overflows at 2038-01-19 03:14:07 UTC. Old embedded software, database columns with 32-bit fields and some file formats hit this limit; use 64 bits.
Unix time does not count leap seconds: every day has exactly 86,400 seconds. A leap second written as 23:59:60 gets the same Unix stamp as the previous second or repeats it.

Time zone rules come from the IANA database as shipped with your browser version and can change; this tool should not be the sole basis for legally, financially or security-critical decisions. For very old dates (before 1900) local time is calculated with historical offsets and may differ from common usage.

Is date and time data flowing inconsistently between your systems? We can clarify time zones, timestamp formats and mapping rules together.

Request a call

How to use it

A
Paste a Unix timestamp or a date; the tool guesses the unit from the size, and you can choose it manually if needed.
B
See the output in all formats and the local time in your chosen time zones with the UTC offset; you can add and remove zones.
C
If there is a daylight saving change or a unit ambiguity, read the warning and choose your storage format accordingly.

What is a Unix timestamp?

A Unix timestamp is the number of seconds since 1970-01-01 00:00:00 UTC (the Unix epoch). It corresponds to one instant and is independent of time zones; it shows the same instant whichever zone it is read in. That is why it is the safest representation between systems.

Many systems keep the same instant in different units: JavaScript and Java use milliseconds, many databases and Python's time.time() use seconds (fractional), Go's UnixNano gives nanoseconds. Assuming the wrong unit gives results such as 1970 or the year 50000.

How the unit is guessed

In automatic mode the size of the whole part decides: below 10¹¹ it is seconds (up to the year 5138), below 10¹⁴ milliseconds, below 10¹⁷ microseconds, otherwise nanoseconds. For present-day stamps this separates reliably by digit count (10, 13, 16, 19).

The guess is wrong for milliseconds before 1973 (taken as seconds). That is why, for a number input, the tool also lists the date that results in each of the four units; pick the one that is the date you expected.

Time zone and daylight saving traps

Converting a local time to an instant needs a time zone, and a daylight saving change creates two special cases: a skipped hour never happens, a repeated hour happens twice. The tool warns about both and shows the two possible instants for an ambiguous time.

Turkey has used UTC+3 all year since 2016 and has no daylight saving; Germany moves clocks forward on the last Sunday of March and back on the last Sunday of October. Zone rules change over time, so store the IANA zone name rather than the offset.

FAQ

Is the value I enter sent anywhere?: No. The conversion and the time zone calculation run on your device with your browser's built-in functions; the value you type is not sent over the network or stored.
Why does the tool take it for milliseconds instead of seconds (or the other way round)?: The unit is guessed only from the size of the number: 10-digit numbers are seconds, 13-digit numbers milliseconds, and so on. If the date is far from what you expected, choose the unit manually under "Unit of the number"; the tool also lists the reading in each unit.
What is the Year 2038 problem?: Systems that keep seconds in a signed 32-bit integer overflow at 2038-01-19 03:14:07 UTC (2³¹−1 seconds) and the counter turns negative. Modern systems use 64 bits; old embedded devices, 32-bit database fields and some file formats are at risk. The tool flags values beyond this limit.
Why is a local time "ambiguous" or "never happens"?: When daylight saving starts, clocks are put forward (e.g. 02:00 → 03:00) and the local times in between never happen. When it ends, clocks are put back (03:00 → 02:00) and the local times in between happen twice. In both cases converting from the local time alone to an instant is not unique; use an offset or UTC.
What is the difference between a UTC offset and an IANA time zone?: An offset (+03:00) is the difference at that moment. An IANA zone (Europe/Berlin) is the name of the offset and daylight saving rules as they change over time. For a past instant an offset is enough; to store a future local appointment you also need the zone name, because the rules can change.
Does Unix time count leap seconds?: No. In Unix time every day has exactly 86,400 seconds; a leap second takes the same value as the previous second or repeats it. This tool also reads second 60 as the start of the next minute.

Let's make time flow consistently between your systems

We design timestamp, time zone and data mapping rules between ERP, SCADA, CRM and third-party systems together with you. Let's talk through your current flow in a free discovery call.

Request a call Explore CRM / ERP integration →