Overview

If you are upgrading Python and want to reinstall all your previously installed modules, you can use pip freeze to capture your current environment and restore it later.

These examples assume Windows PowerShell.

Step 1 – Freeze Your Current Environment

python -m pip freeze > requirements.txt

If multiple versions are installed:

py -3.12 -m pip freeze > requirements.txt

Step 2 – Install or Upgrade Python

py -3.13 --version

Step 3 – Reinstall All Modules

py -3.13 -m pip install -r requirements.txt

Recommended: Use a Virtual Environment

python -m venv .venv
\.venv\Scripts\Activate.ps1
pip freeze > requirements.txt

Recreate after upgrade:

py -3.13 -m venv .venv
\.venv\Scripts\Activate.ps1
pip install -r requirements.txt

Final Recommendation

  • Always use virtual environments
  • Commit requirements.txt to version control
  • Recreate environments instead of copying site-packages