Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Documentation Status

This is the uncertainties Python package, which performs transparent calculations with uncertainties (aka "error propagation"):

>>> from uncertainties import ufloat
>>> from uncertainties.umath import *  # sin(), etc.
>>> x = ufloat(1, 0.1)  # x = 1+/-0.1
>>> print 2*x
>>> sin(2*x)  # In a Python shell, "print" is optional

This package also automatically calculates derivatives of arbitrary functions:

>>> (2*x+1000).derivatives[x]

The main documentation is available at

Git branches

The release branch is the latest stable release. It should pass the tests.

master* branches in the Github repository are bleeding-edge, and do not necessarily pass the tests. The master branch is the latest, relatively stable versions (while other master* branches are more experimental).

Other branches might be present in the GitHub repository, but they are typically temporary and represent work in progress that does not necessarily run properly yet.


This package and its documentation are released under the Revised BSD License.

Voluntary donations

If you find this open-source software useful (e.g. in saving you time or helping you produce something valuable), please consider donating $10 or more to help contribute to the maintenance of the package.