Students willing to study in germany, need to block some amount in a bank before they can apply for visa. How much is this amount? Some sites say 720 EURO/month x 12 months = 8640 EURO needs to be blocked, while others say 720 EURO/month x total number of months one need to stay in germany (or duration of the course).
Following the link provided in https://uk.diplo.de/uk-en/02/visa/8-study-research/info-students to https://www.auswaertiges-amt.de/en/sperrkonto/388600, the requirement is:
The blocked account must have sufficient credit in order to cover the costs arising for the duration of your planned stay in Germany, unless other proof of financial support is presented in the visa procedure. Certain standard rates apply (for students, the presumed annual requirement that must be paid into the blocked account is currently 8640 euros).
The account may only permit the withdrawal of a certain amount per month (currently 720 euros for students).