Unix timestamp converter for Next.js & Supabase. In your browser.
Convert seconds, milliseconds and offset-aware dates, with IANA time zones, Now and a PostgreSQL timestamptz value. No uploads — free, no sign-up.
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Millisecond precision, JavaScript Date range. Device clock and browser time-zone data apply; leap seconds are not represented.
How to use
- Choose seconds, milliseconds or an ISO date with an explicit Z or numeric offset.
- Enter an IANA display zone, such as UTC or America/Montevideo, then Convert timestamp or Now.
- Read the epoch, UTC ISO date, zoned display and timestamptz value. Copy or download locally.
Reference documentation
Frequently asked questions
Is this free, and does anything leave my browser?
Free, no sign-up. Inputs and outputs stay in your browser, with no processing endpoint or upload. Copy and download are local. Usage events contain only a fixed tool name and action, never your data.
Are Unix timestamps in seconds or milliseconds?
Unix time is commonly expressed in seconds, while JavaScript Date uses milliseconds. Select the unit explicitly: the converter never guesses from the number of digits. Fractional seconds are accepted to three decimal places.
Does choosing a time zone change the epoch?
No. Epoch identifies an instant. The IANA time zone changes only the display and accounts for the zone rules supplied by your browser. ISO output always uses UTC.
How do I convert a date during daylight-saving changes?
Include an explicit offset, for example 2026-11-01T01:30:00-04:00 or -05:00. Bare local dates are rejected because an IANA clock time can be ambiguous or nonexistent during a DST transition.
How does this help with Supabase timestamptz?
PostgreSQL timestamptz represents an instant. The converter emits a UTC ISO value with a ::timestamptz cast for review. PostgreSQL display depends on the session time zone; keep an original zone separately if your app needs it.
Does Now use the server clock?
No. Now takes Date.now() from your device, at the moment you click. It is a snapshot, not a ticking clock, and its accuracy depends on your device clock.
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