How to Parse ISO 8601 Date Strings
ISO 8601 Parsing
What is ISO 8601?
ISO 8601 is the international standard for date and time strings. Examples: 2026-07-03T12:00:00Z (UTC) or 2026-07-03T08:00:00-04:00 (with offset).
When to Use This Tool
Parse ISO strings from API responses, OpenAPI specs, database exports, and config files. Validate format before deployment and compare times across time zones. Output includes Unix timestamp and local time equivalents.
Common Mistakes
- Omitting timezone — strings without Z or offset are parsed as local browser time
- Using non-ISO regional formats (MM/DD/YYYY) expecting ISO parsing
- Microsecond precision — JavaScript Date supports milliseconds only
Developer Tips
- Always include Z or an explicit offset in APIs for unambiguous storage
- Store UTC; convert to local zones only for display
- Pair with Unix Timestamp tool to convert parsed results to seconds
Frequently asked questions
What ISO 8601 formats are supported?
Any format supported by JavaScript Date.parse(), including Z suffix for UTC and +/- timezone offsets.
What happens if there is no timezone?
Strings without a timezone are interpreted as local time in your browser.
Is date-only input supported?
Date-only strings like 2026-07-03 are parsed as UTC midnight. Include Z or an offset for unambiguous datetimes.