Convert Human Time to Unix Time

“Browser Local” uses whatever timezone your OS is set to – quick and obvious. An explicit IANA zone like America/New_York gives you a specific zone regardless of where you are, and the tool correctly applies DST at the moment you typed. Use explicit zones when working with scheduled events across regions.

For IANA zones, we use Intl.DateTimeFormat to ask the browser for the actual UTC offset at the moment you typed – not a static offset. So 2026-03-08T02:30 America/New_York (spring-forward day) gets the post-transition offset automatically.

FILETIME is a 64-bit integer counting 100-nanosecond intervals since 1601-01-01 UTC. Windows APIs, Active Directory, NTFS timestamps, and Office document metadata all use it. We compute it with BigInt so the full 64-bit precision is preserved.

Because they exceed JavaScript’s safe integer range (2^53-1). Microseconds since epoch today are about 1.7 × 10^15, which is still safe, but nanoseconds (1.7 × 10^18) are not. We use BigInt internally and render the final value as a string so no precision is lost.

At 2038-01-19T03:14:07Z, Unix seconds will exceed 2,147,483,647 – the maximum positive value of a signed 32-bit integer. Systems still using 32-bit timestamps will wrap around to negative numbers on that date. The tool flags any seconds value beyond that threshold so you can audit vulnerable code paths.

Yes. Dates before the epoch produce negative Unix timestamps. 1969-12-31T23:59:59Z = -1 seconds. JavaScript’s Date goes back to -100,000,000-01-01 and forward to 275,760-09-13, and this tool follows the same range.

No. Everything runs in your browser using built-in JavaScript (Date, Intl.DateTimeFormat, BigInt). Open DevTools → Network and watch zero requests fire. Safe for scheduled event data, audit logs, anything sensitive.

Yes. Total bundle is under 20 KB. Once the page (and timezone list from your OS’s ICU data) loads, you can disconnect. The Intl APIs are bundled with your browser; no network calls for timezone info.

RFC 2822 (Fri, 24 Apr 2026 09:00:00 GMT) is the older format used in email headers and HTTP Date: headers. ISO 8601 (2026-04-24T09:00:00.000Z) is the modern standard used by most APIs and databases. We show both so you can drop into whichever system you’re talking to.

Use the companion Unix-to-Human converter in the same Time category. Paste a Unix seconds or milliseconds value, pick your display timezone, get the same 9 formats back in human-readable form. Round-trip is exact at the millisecond.