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Simple module to parse ISO 8601 dates

Project description

Simple module to parse ISO 8601 dates

This module parses the most common forms of ISO 8601 date strings (e.g. 2007-01-14T20:34:22+00:00) into datetime objects.

>>> import iso8601
>>> iso8601.parse_date("2007-01-25T12:00:00Z")
datetime.datetime(2007, 1, 25, 12, 0, tzinfo=<iso8601.Utc>)

See the LICENSE file for the license this package is released under.

If you want more full featured parsing look at:

Parsed Formats

You can parse full date + times, or just the date. In both cases a datetime instance is returned but with missing times defaulting to 0, and missing days / months defaulting to 1.




  • YYYY-MM (defaults to 1 for the day)

  • YYYY (defaults to 1 for month and day)


  • hh:mm:ss.nn

  • hhmmss.nn

  • hh:mm (defaults to 0 for seconds)

  • hhmm (defaults to 0 for seconds)

  • hh (defaults to 0 for minutes and seconds)

Time Zones

  • Nothing, will use the default timezone given (which in turn defaults to UTC).

  • Z (UTC)

  • +/-hh:mm

  • +/-hhmm

  • +/-hh

Where it Differs From ISO 8601

Known differences from the ISO 8601 spec:

  • You can use a “ “ (space) instead of T for separating date from time.

  • Days and months without a leading 0 (2 vs 02) will be parsed.

  • If time zone information is omitted the default time zone given is used (which in turn defaults to UTC). Use a default of None to yield naive datetime instances.




  1. poetry install

  2. poetry run nox

Note that you need all the pythons installed to perform a tox run (see below). pyenv helps hugely, use pyenv install for the versions you need then use ‘pyenv local version …’ to link them in (the tox-pyenv plugin will pick them up).

Alternatively, to test only with your current python:

  1. poetry install

  2. pytest


  1. Ensure there is a new version committed to main (use poetry version <action> to bump).

  2. Ensure README.rst changelog is up to date.

  3. Note new and previous version.

  4. rm -rf dist

  5. poetry build

  6. git log –oneline $LAST_VERSION..@ > git_log.txt

  7. gh release create –notes-file git_log.txt –title $(poetry version -s) $(poetry version -s) dist/*

  8. poetry publish

Supported Python Versions

Tested against:

  • Python 3.6

  • Python 3.7

  • Python 3.8

  • Python 3.9

  • Python 3.10

  • Python 3.11

  • PyPy 3

Python 3 versions < 3.6 are untested but should work.






  • Add missing py.typed file (as per PEP 561), keeps mypy happy :D


  • Drop python < 3.6 support

  • Add type annotations to code

  • Remove external type annotations in pyi

  • Switch to poetry for packaging

  • Simplify internals and remove old compatability code

  • Switch to nox for testing

  • Lots of small project development changes



  • Include .pyi files in built wheels and source tarballs


  • Add GitHub build actions for project

  • Add project URLs in (thanks to Steve Piercy)

  • Update README links (thanks to Steve Piercy)

  • Fix handling of README in (encoding fun in 3.5, 3.6 and pypy3)

  • Fix README links (thanks to Chris Barker)

  • Add Python 3.9 to test matrix (thanks to Luciano Mammino)

  • Add type hints (thanks to Brett Cannon)

  • Derive ParseError from ValueError (thanks to Lex Robinson)


  • Move to GitHub ( Thanks go to Martin Häcker for pointing out the bitbucket project had been deleted by Atlassian!

  • Remove python 2.6, 3.2, 3.3 and 3.4 from tests

  • Add python 3.7 and 3.8 to tests










  • The default_timezone argument wasn’t being passed through correctly, UTC was being used in every case. Fixes issue 10.


  • Fixed the microsecond handling, the generated microsecond values were way too small. Fixes issue 9.


  • Adding ParseError to __all__ in iso8601 module, allows people to import it. Addresses issue 7.

  • Be a little more flexible when dealing with dates without leading zeroes. This violates the spec a little, but handles more dates as seen in the field. Addresses issue 6.

  • Allow date/time separators other than T.


  • When parsing dates without a timezone the specified default is used. If no default is specified then UTC is used. Addresses issue 4.

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