‘pip’ is not recognized as an internal or external command

pip is already installed if you’re using Python 2 >=2.7.9 or Python 3 >=3.4. In case your pip command is not recognised by Windows CMD, then most probably the Python Scripts path is not set in the system variables:

You need to add the path of your pip installation to your PATH system variable. By default, pip is installed to C:\Python34\Scripts\pip (pip now comes bundled with new versions of python), so the path “C:\Python34\Scripts” needs to be added to your PATH variable.

To check if it is already in your PATH variable, type echo %PATH% at the CMD prompt

To add the path of your pip installation to your PATH variable, you can use the Control Panel or the setx command. For example:

setx PATH "%PATH%;C:\Python34\Scripts"

Note: According to the official documentation, “[v]ariables set with setx variables are available in future command windows only, not in the current command window”. In particular, you will need to start a new cmd.exe instance after entering the above command in order to utilize the new environment variable.

via [stackoverflow]