With this compact tool you can split your pdf files.
It is written in Python 3 and uses Python's tkinter for the GUI realization.
The PyPDF2 library needs to be installed beforehand. Use the package manager pip to install PyPDF2.
pip install PyPDF2
Open your cmd and navigate to the folder where pdfsplitter.py is. Now simply type:
python pdfsplitter.py
The GUI will open up and you can start splitting your files.