How to Install OpenCV on Ubuntu

OpenCV is the standard open-source computer vision library for C++ and Python—used for image processing, camera capture, object detection, and machine-learning pipelines. On Ubuntu you can install it from apt (fastest), pip in a virtual environment (newer wheels), or a source build (maximum control). The package name python3-opencv replaced legacy python-opencv on modern Ubuntu (Ask Ubuntu).

This guide shows how to install OpenCV on Ubuntu, verify Python and C++ toolchains, locate headers and libraries, and avoid common import errors. Commands below were tested on Ubuntu 25.04.

Quick command summary

Prerequisites

• Python 3 for python3-opencv or pip wheels.
• build-essential and cmake only if you compile OpenCV from source (install CMake guide).
• For GUI functions (cv2.imshow), a desktop with libGL / Mesa installed.

Confirm your LTS or interim release with our check Ubuntu version guide when the steps below name a specific Ubuntu codename.

Choose an install method

For embedded and server boards that do not need a custom build, the simple apt pair libopencv-dev + python3-opencv is usually enough.

Step 1: Install OpenCV from apt (recommended)

Refresh indexes and inspect candidates:

sudo apt update
apt-cache policy libopencv-dev python3-opencv

Example on Ubuntu 25.04:

libopencv-dev:
 Candidate: 4.10.0+dfsg-5
 Version table:
 4.10.0+dfsg-5 500
 500 http://archive.ubuntu.com/ubuntu plucky/universe amd64 Packages
python3-opencv:
 Candidate: 4.10.0+dfsg-5

Install with apt:

sudo apt install -y libopencv-dev python3-opencv

Do not run sudo apt install python-opencv on Ubuntu 20.04+—that name is gone (Ask Ubuntu #1330968).

Step 2: Verify Python OpenCV

python3 -c "import cv2; print('cv2 version:', cv2.__version__); print('path:', cv2.__file__)"

cv2 version: 4.10.0
path: /usr/lib/python3/dist-packages/cv2.cpython-313-x86_64-linux-gnu.so

Interactive check:

python3

import cv2
print(cv2.__version__)
exit

4.10.0

Step 3: Verify C++ / pkg-config paths

Where OpenCV lives after an apt install (Ask Ubuntu: where is OpenCV installed):

Resolve the executable path with which; the which command explains PATH search order and differences from command -v.

opencv_version
pkg-config --modversion opencv4
pkg-config --list-all | grep -i opencv
ls /usr/include/opencv4/opencv2/ | head -5
which opencv_version

4.10.0
4.10.0
opencv4 OpenCV - Open Source Computer Vision Library
alphamat.hpp
aruco
aruco.hpp
bgsegm.hpp
bioinspired
/usr/bin/opencv_version

Compile flags for a C++ project:

pkg-config --cflags --libs opencv4

-I/usr/include/opencv4 -lopencv_stitching -lopencv_alphamat ... -lopencv_core

Example minimal compile (requires g++ and libopencv-dev):

cat > /tmp/opencv-hello.cpp <<'EOF'
#include <opencv2/opencv.hpp>
#include <iostream>
int main {
 std::cout << "OpenCV " << CV_VERSION << std::endl;
 return 0;
}
EOF
g++ /tmp/opencv-hello.cpp -o /tmp/opencv-hello $(pkg-config --cflags --libs opencv4)
/tmp/opencv-hello

Expected output shape: OpenCV 4.10.0.

Step 4: Install OpenCV with pip (virtual environment)

Ask Ubuntu notes pip as the quickest path when you only need Python and want a newer wheel than apt.

sudo apt install -y python3-venv python3-pip
python3 -m venv ~/opencv-venv
source ~/opencv-venv/bin/activate
pip install --upgrade pip
pip install opencv-python
python3 -c "import cv2; print('pip cv2:', cv2.__version__)"

pip cv2: 4.13.0

For contrib modules via PyPI :

pip install opencv-contrib-python

Deactivate when done: deactivate.

Step 5: Build OpenCV from source (advanced)

Build from GitHub when apt is too old, you need a specific commit, or you must disable/enable codecs and CUDA flags manually. Follow the official Ubuntu setup tutorial and Linux install guide.

Install build dependencies:

sudo apt update
sudo apt install -y build-essential cmake git pkg-config \
 libgtk-3-dev libavcodec-dev libavformat-dev libswscale-dev \
 libv4l-dev libxvidcore-dev libx264-dev libjpeg-dev libpng-dev libtiff-dev \
 libatlas-base-dev gfortran python3-dev python3-numpy

Clone and configure (example layout):

mkdir -p ~/opencv_build && cd ~/opencv_build
git clone --depth 1 --branch 4.10.0 https://github.com/opencv/opencv.git
git clone --depth 1 --branch 4.10.0 https://github.com/opencv/opencv_contrib.git
mkdir -p opencv/build && cd opencv/build
cmake -D CMAKE_BUILD_TYPE=Release \
 -D CMAKE_INSTALL_PREFIX=/usr/local \
 -D OPENCV_EXTRA_MODULES_PATH=~/opencv_build/opencv_contrib/modules \
 -D OPENCV_GENERATE_PKGCONFIG=ON \
 -D BUILD_EXAMPLES=OFF ..
make -j"$(nproc)"
sudo make install
sudo ldconfig

Verify a /usr/local install:

pkg-config --modversion opencv4
/usr/local/bin/opencv_version

Source installs land under /usr/local/include/opencv4 and /usr/local/lib—which can shadow apt packages if /usr/local precedes /usr on PKG_CONFIG_PATH. Remove or adjust paths when switching back to apt.

Uninstall

APT packages:

sudo apt purge -y python3-opencv libopencv-dev
sudo apt autoremove -y

pip virtual environment:

deactivate 2>/dev/null || true
rm -rf ~/opencv-venv

Manual /usr/local source install:

sudo rm -rf /usr/local/include/opencv4 /usr/local/lib/libopencv* /usr/local/bin/opencv_*
sudo ldconfig

See how to remove software on Ubuntu for broader cleanup patterns across apt, Snap, and Flatpak.

Troubleshooting

References

• OpenCV — Install OpenCV-Python in Ubuntu
• OpenCV — Installation in Linux (C++)
• Ask Ubuntu: Installing OpenCV
• Ask Ubuntu: python-opencv on 20.04
• Ask Ubuntu: Where is OpenCV installed?
• ,

Summary

The fastest way to install OpenCV on Ubuntu is sudo apt install -y libopencv-dev python3-opencv, which on Ubuntu 25.04 provides OpenCV 4.10.0 with headers in /usr/include/opencv4 and cv2 under /usr/lib/python3/dist-packages. Confirm with opencv_version, pkg-config --modversion opencv4, and python3 -c "import cv2; print(cv2.__version__)".

Use pip install opencv-python (or opencv-contrib-python) inside a virtual environment when you need a newer PyPI wheel. Compile from GitHub source only when apt and pip cannot meet your module, codec, or GPU requirements.