civil service generally does not pay more for masters (even if relevant) unless asked for in the JD. otherwise your 'master dean listed' may be good for your long term progression.

for a start to help you estimate, you may want to provide us with the following:

degree class from your undergrad uni + gender + 3 years experience (maybe averagely 150-200 per year of experience) - this is important because they have a strict formula in estimating salary which works with the unit's hiring budget.

one's base salary will be determined by the degree class and uni (e.g., SIM will be paid 2.5-2.6k all the way to NUS FCH getting 3.7-3.9k: read earlier pages for an estimation) + 200 (if you served NS) + 150*3 (for your experience). however, don't be surprised if the civil service low-ball your salary since they may consider <3 experience to be a fresh grad role.

also, if you are looking at the specialised services (MFA, Stats, Economist, Engineer, Legal, Intel and etc) then add another 20% to the quote above.

they may consider your last drawn, but not often. if you read earlier pages, some people are getting a pay cut to join the civil service so that is not uncommon.