opencv-python for Windows on Arm64 (unofficial build)

pip install opencv-python fails on Windows on Arm because the official package has no win_arm64 wheel. This repository provides a wheel built natively on a Windows 11 Arm64 laptop, plus the steps and the one-line fix needed to build it yourself.

Unofficial and experimental. Not made or endorsed by the OpenCV team. "OpenCV" is a trademark of its owners. Tested only lightly (see below).

Install

Requirements: Windows 11 on Arm64 and Python 3.12 (64-bit Arm Python).

Download the .whl file from the Releases page, then:

python -m pip install opencv_python-4.14.0+031876b-cp312-cp312-win_arm64.whl

The package name stays opencv-python, so libraries that depend on it (for example Ultralytics) accept it.

Check:

python -c "import cv2; print(cv2.__version__)"

What was tested

On an ASUS ProArt (Windows 11 on Arm, Python 3.12.16, numpy 2.5.4):

• import cv2 -> 4.14.0
• cv2.resize on a numpy image
• cv2.imencode('.jpg', ...)

More testing (Ultralytics training) is in progress.

Build details

Item	Value
Source	opencv-python master, commit 031876b (4 Sep 2026); OpenCV 4.14.0
Compiler	Visual Studio 2022 Build Tools 17.14, MSVC v143 ARM64, Windows SDK 10.0.26100
CMake	4.4.4 (from pip)
CPU features	baseline NEON (FP16 / BF16 / DOTPROD dispatch not available with this compiler)
GUI	Win32 UI (not headless)
Video I/O	Media Foundation and DirectShow yes; FFmpeg no (no prebuilt Arm64 FFmpeg DLL)
Linking	static, everything in one cv2.pyd

Build it yourself

1. Install Git for Windows (ARM64) and Visual Studio 2022 Build Tools with "Desktop development with C++" and the individual component "MSVC v143 - VS 2022 C++ ARM64/ARM64EC build tools (Latest)".
2. Get the source (use a short path):

   git config --global core.longpaths true
   mkdir C:\cv; cd C:\cv
   git clone --recursive https://github.com/opencv/opencv-python.git
   cd opencv-python

3. Apply the fix in setup_py_arm64.patch: setup.py expects an FFmpeg DLL on every Windows build, which does not exist on Arm64. Save the patch file into C:\cv, then:

   git apply ..\setup_py_arm64.patch

   (or edit the line by hand: if os.name == "nt" becomes if os.name == "nt" and platform.machine() != "ARM64" in the opencv_videoio_ffmpeg entry.)
4. Install the build tools into your Python environment. The pinned build requirement numpy 2.0.2 has no Arm64 wheel, so we build without isolation:

   python -m pip install --upgrade pip numpy "setuptools<70" packaging scikit-build cmake wheel

5. Build:

   $env:CMAKE_GENERATOR = "Visual Studio 17 2022"
   python -m pip wheel . --verbose --no-deps --no-build-isolation -w wheels

   The compile took about 8 minutes on a Snapdragon-class laptop.
6. Afterwards, restore a newer setuptools if other packages need it (python -m pip install "setuptools>=77").

Errors we hit, and the fixes

Error	Cause	Fix
The BaseOutputPath/OutputPath property is not set ... Platform='ARM64'	ARM64 MSVC component not installed	add "MSVC v143 ARM64/ARM64EC build tools (Latest)"
Not found: 'bin/opencv_videoio_ffmpeg\d{4}_64\.dll'	setup.py always expects FFmpeg on Windows	the patch above
pip tries to build numpy 2.0.2 from source	no Arm64 wheel for the pinned build numpy	--no-build-isolation with your own numpy

Licence

Build notes and patch: MIT (the patch modifies opencv-python's MIT-licensed setup.py). The wheel contains OpenCV (Apache 2.0) and third-party libraries; their licence texts are included in the wheel. See LICENSE.

Credits

OpenCV and opencv-python are made by their contributors. This repository only documents a Windows-on-Arm64 build. The goal is to get this fixed upstream.