How to Install `threadpoolctl` in Python

v3.6.0 General Purpose Python >=3.9 BSD-3-Clause

threadpoolctl

Install pip install threadpoolctl

What is threadpoolctl?

threadpoolctl

Python helpers to limit the number of threads used in the threadpool-backed of common native libraries used for scientific computing and data science (e.g. BLAS and OpenMP).

Fine control of the underlying thread-pool size can be useful in workloads that involve nested parallelism so as to mitigate oversubscription issues.

- For users, install the last published version from PyPI:

Documentation → PyPI page → Author: Thomas Moreau

Quick Start

Minimal example to get started with threadpoolctl:

import threadpoolctl

print(threadpoolctl.__version__)

Installation

pip (standard)

pip install threadpoolctl

Virtual environment (recommended)

python -m venv venv
source venv/bin/activate   # Windows: venv\Scripts\activate
pip install threadpoolctl

pip3

pip3 install threadpoolctl

conda

conda install -c conda-forge threadpoolctl

Poetry

poetry add threadpoolctl

Verify the Installation

After installing, confirm the package is available:

python -c "import threadpoolctl; print(threadpoolctl.__version__)"

If this prints a version number, installation succeeded. If you see a ModuleNotFoundError, see the errors section below.

Installation Errors

Common errors when installing threadpoolctl with pip.

ModuleNotFoundError: No module named 'threadpoolctl'

Cause: The package is not installed in the current Python environment.

Fix: Run pip install threadpoolctl. If using a virtual environment, ensure it is activated first.

ModuleNotFoundError: No module named 'threadpoolctl' (installed but still failing)

Cause: pip installed the package into a different Python than the one running your script.

Fix: Use python -m pip install threadpoolctl to install into the interpreter you are running.

ImportError: cannot import name 'X' from 'threadpoolctl'

Cause: The function or class does not exist in the installed version.

Fix: Check the version with pip show threadpoolctl and upgrade with pip install --upgrade threadpoolctl.

pip: command not found

Cause: pip is not in PATH or Python was not added to PATH during installation.

Fix: Try python -m pip install threadpoolctl. On macOS/Linux try pip3.

PermissionError: [Errno 13] Permission denied

Cause: No write access to the system Python package directory.

Fix: Use a virtual environment, or add --user: pip install --user threadpoolctl

SSL: CERTIFICATE_VERIFY_FAILED

Cause: pip cannot verify PyPI's SSL certificate — common behind corporate proxies.

Fix: Try: pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org threadpoolctl

Recent Releases

Version	Released
`3.6.0` latest	2025-03-13
`3.5.0`	2024-04-29
`3.4.0`	2024-03-20
`3.3.0`	2024-02-14
`3.2.0`	2023-07-13

Full release history on PyPI →

Manage threadpoolctl

Upgrade to latest version

pip install --upgrade threadpoolctl

Install a specific version

pip install threadpoolctl==3.6.0

Uninstall

pip uninstall threadpoolctl

Check what is installed

pip show threadpoolctl

Last updated: 2026-04-11 • Data from PyPI

How to Install threadpoolctl in Python