At least in Germany, depending on contract, monthly payments vary heavily. For instance the labour agreement for the automotive industry contains a 13th salary at christmas time, vacation pay in summer, a bonus in spring depending on company performance, a potential bonus if you pass on some vacation days and more. Other contracts only have a monthly salary and no bonuses. My contract has only one bonus depending on company performance in April while my wife gets 12.8 monthly salaries (1.8x salary in November as end-of-year bonus). To compare job offers in any way, you can only go with the annual number.
We may never know ( lemmy.world )