Unix Timestamp Converter
Convert Unix seconds, milliseconds, ISO 8601, and calendar dates. See UTC and local time together, with explicit timezone rules and exact copyable values.
Select the units explicitly. Unix input accepts integers only, including negative values. ISO input requires seconds and Z or an offset, such as +05:30.
Browser timezone: detected when the tool loads.
Local dates use this timezone’s rules. Skipped or repeated daylight-saving times are rejected; choose ISO with an explicit offset instead.
Current time captures one instant from your device clock. The relative display updates while you keep that result open.
Choose your input units or timezone, then Convert.
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Make time
unambiguous.
Seconds and milliseconds are different units.
Unix time counts from January 1, 1970 at 00:00:00 UTC. 1704067200 seconds and 1704067200000 milliseconds both mean January 1, 2024 at midnight UTC. This converter never guesses the units from the number of digits. Negative values represent earlier instants. Spaces, decimal input, and exponent notation are rejected; use integer milliseconds when you need subsecond precision.
Tell a date which timezone to use.
ISO mode requires a complete instant such as 2024-01-01T00:00:00Z or 2024-01-01T05:30:00+05:30. Calendar modes explicitly interpret your date and time as UTC or your browser’s local timezone. Invalid dates such as February 30 are rejected instead of rolling into the next month. ISO input supports years 0000–9999; the browser’s calendar fields support 0001–9999. Both accept up to three fractional second digits.
Daylight saving needs an explicit choice.
A local clock can skip an hour or repeat one. This tool rejects nonexistent or ambiguous local wall times, including nearby offset transitions up to 24 hours, so you can supply an ISO timestamp with the intended offset. Timezone rules come from your device; future rule changes may alter how a local calendar date is interpreted. The UTC ISO output remains an unambiguous instant.
Integer timestamps support JavaScript Date’s range of ±8,640,000,000,000,000 milliseconds. The ISO result may use an extended year outside the four-digit calendar input range. Unix seconds output preserves milliseconds as fractional digits. The relative description is approximate (months use 30 days, years 365 days), and Current time follows your device clock. Leap seconds are not represented. No history, storage, or network requests contain your input.