ISO 8601 Formatter
Format a date and time as a standard ISO 8601 string.
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About this tool
ISO 8601 is the standard used by JSON APIs, databases and most programming languages — YYYY-MM-DDTHH:mm:ssZ for UTC, or with a +HH:mm offset for local time.
The same moment can be written several ways. The UTC form ending in Z is the safest for storing and exchanging data. The offset form keeps the local clock time while still pinning down the exact moment. Basic format drops the separators and is common in file names. Week dates (2026-W42-5, the Friday of week 42) are used in business planning, and ordinal dates (2026-289, the 289th day) appear in logistics and manufacturing.