How does it know whether my number is seconds or milliseconds?

Detection uses the number of whole-number digits: up to eleven suggests seconds, twelve to fourteen milliseconds, fifteen to seventeen microseconds and eighteen or more nanoseconds. These are heuristics for modern timestamps; historical and far-future values can mislead. The interpreted unit is shown. Choose the actual unit explicitly when you know it.

Can I convert a date back to a timestamp?

Yes. Type a date like 2026-08-30 14:30, 30 Aug 2026 2:30 PM or 2026-08-30T14:30Z and you get the epoch seconds and milliseconds alongside the other formats. A date that names no zone is read in the zone chosen under Zone, Local or UTC; one that names its own keeps it. An impossible date, such as 30 February, is refused rather than rolled into March.

Does it handle time zones?

Local uses your browser’s time zone; UTC uses universal time. Numeric timestamps name the same instant in either display. A written date without a zone is interpreted in the selected zone. Skipped or repeated local times are refused: use an explicit offset to choose the instant. Supported numeric offsets run from -12:00 to +14:00. Named abbreviations use fixed offsets, such as CST = -06:00, and do not identify a region or its daylight-saving rules. Only the zone choice is saved; unusable stored choices are kept until you explicitly forget them.

What about dates before 1970?

Negative timestamps work and resolve correctly: -86400 is midnight UTC on 31 December 1969, which the Local setting shows as 30 December in any zone behind UTC.

Is anything sent to a server?

No. The clock and every conversion run in your browser.

What happens after 2038?

Nothing here. The 2038 problem affects systems storing timestamps in a signed 32-bit integer, which overflows on 19 January 2038. This tool uses JavaScript numbers and handles dates far beyond that, as well as negative timestamps for dates before 1970.

How much precision is kept?

Every instant is floored to a whole millisecond. For example, -1.5 milliseconds becomes -2 milliseconds, and fractional microseconds or nanoseconds below a millisecond are not retained. Relative output uses fixed 30-day months and 365-day years, so it is approximate duration wording rather than calendar arithmetic. Historical local offsets with seconds use exact UTC ISO output instead of rounding the offset.

Epoch Converter

Convert Unix timestamps to readable dates and dates back to timestamps, with a live current-time clock. Read seconds, milliseconds, microseconds or nanoseconds; automatic detection is a magnitude heuristic, and the Unit control lets you choose explicitly.

Current Unix time · your local time

Convert a timestamp or date

Unit

Zone

Common questions

How does it know whether my number is seconds or milliseconds?: Detection uses the number of whole-number digits: up to eleven suggests seconds, twelve to fourteen milliseconds, fifteen to seventeen microseconds and eighteen or more nanoseconds. These are heuristics for modern timestamps; historical and far-future values can mislead. The interpreted unit is shown. Choose the actual unit explicitly when you know it.
Can I convert a date back to a timestamp?: Yes. Type a date like 2026-08-30 14:30, 30 Aug 2026 2:30 PM or 2026-08-30T14:30Z and you get the epoch seconds and milliseconds alongside the other formats. A date that names no zone is read in the zone chosen under Zone, Local or UTC; one that names its own keeps it. An impossible date, such as 30 February, is refused rather than rolled into March.
Does it handle time zones?: Local uses your browser’s time zone; UTC uses universal time. Numeric timestamps name the same instant in either display. A written date without a zone is interpreted in the selected zone. Skipped or repeated local times are refused: use an explicit offset to choose the instant. Supported numeric offsets run from -12:00 to +14:00. Named abbreviations use fixed offsets, such as CST = -06:00, and do not identify a region or its daylight-saving rules. Only the zone choice is saved; unusable stored choices are kept until you explicitly forget them.
What about dates before 1970?: Negative timestamps work and resolve correctly: -86400 is midnight UTC on 31 December 1969, which the Local setting shows as 30 December in any zone behind UTC.
Is anything sent to a server?: No. The clock and every conversion run in your browser.
What happens after 2038?: Nothing here. The 2038 problem affects systems storing timestamps in a signed 32-bit integer, which overflows on 19 January 2038. This tool uses JavaScript numbers and handles dates far beyond that, as well as negative timestamps for dates before 1970.
How much precision is kept?: Every instant is floored to a whole millisecond. For example, -1.5 milliseconds becomes -2 milliseconds, and fractional microseconds or nanoseconds below a millisecond are not retained. Relative output uses fixed 30-day months and 365-day years, so it is approximate duration wording rather than calendar arithmetic. Historical local offsets with seconds use exact UTC ISO output instead of rounding the offset.

Exact integer scaling, floored to milliseconds, within JavaScript’s Date range: -8,640,000,000,000,000 to +8,640,000,000,000,000 milliseconds. Automatic units are a heuristic. Zone-free dates use the selected browser-local zone or UTC; ambiguous or skipped local times require a different choice or explicit offset. Relative months and years are approximate.