ISO 8601 Converter
Convert ISO 8601 dates to Unix timestamps and back — no server, no signup, no limits.
ISO 8601 ⇄ Timestamp
Runs entirely in your browserType in either field — the other updates live.
What is ISO 8601?
ISO 8601 is the international standard for representing dates and times unambiguously, published by the International Organization for Standardization.
Because it's structured largest-unit-first (year, then month, then day), ISO 8601 strings sort correctly as plain text — no parsing required to know which date comes first.
- Default date format in JSON, JavaScript, and most databases
- Sortable lexicographically without parsing
Zsuffix means UTC; otherwise an explicit offset is required- Closely related to (and a superset of) RFC 3339
ISO 8601 Format
The T separates date from time; Z means Zulu time (UTC).
How do I convert ISO 8601 to Unix timestamp?
Paste the ISO 8601 string into the converter above — the equivalent Unix timestamp in both seconds and milliseconds appears instantly, along with UTC and local time equivalents.
Frequently Asked Questions
YYYY-MM-DDTHH:mm:ss.sssZ. It's unambiguous, sortable as plain text, and the default date format for JSON APIs, databases, and most programming languages.
+05:00 or -08:00.
YYYY-MM-DDTHH:mm:ssZ form this tool produces, though ISO 8601 permits some formats (like week dates) that RFC 3339 does not. Need the HTTP-header style format instead? Use the RFC 2822 Date Converter.
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