It depends on the requirements of your school. Specifically, it is still the requirement of the tutor. If the tutor asks for 20 thousand words, you have to write 20 thousand words. If the tutor asks you to write 10000, you can write 10000. Just ask your tutor! The most important thing for master's thesis is duplicate checking, and the repetition rate must meet the requirements of the school, otherwise the defense will be postponed. Papertime can be used to check the weight or to lose weight automatically. This is for my master's thesis, and it is still good to use!