In general, € 992.00 for every month of your stay is required as the monthly blocked amount. This is the standard monthly sum required by the German authorities. Please note that only your local embassy, consulate or the local immigration authority can provide you with binding information on the required monthly blocked amount for your individual case.
The "additional basic sum" is an additional amount on your blocked account which only needs to be entered if your local embassy, consulate, or immigration authority has a special request! Please do not enter any "additional basic sum" without a particular request by the embassy. The "additional basic sum" is just a security for the aforementioned entities. Please keep in mind that this sum remains blocked during your time in Germany.