I think there are quite a few readers who are confused about the difference between contributing to their CPF account and topping up their CPF account. I understand their confusion. Once upon a time, I was confused too. 1. There is such a thing as the CPF annual contribution limit. Basically, our mandatory contribution (MC) and voluntary contribution (VC), if any, cannot exceed the annual contribution limit. See: CPF Annual Limit and VC. If we are working, chances are we are contributing to our CPF account. That is required by law. So, it is called mandatory contribution (MC). If our MC does not hit the annual contribution limit, we can do VC to hit that limit. VC can either be done purely to our CPF Medisave Account (MA) which then gives us income tax relief or it can be a regular VC which the CPF Board will apportion to our OA, SA and MA ......