Thanks for the comment.
So as not to lose out, I have done some research on the tax in China. It is somewhat more complex and not consistent throughout the country.
These 2 pages sum the calculation side of it quite nicely:
Individual Income Tax in China - JLJ
Employing Local Personnel in China - JLJ
Anyways, if the base pay is 50,000 RMB, the net take home works out to around 30,755 RMB after paying tax in China. I have yet to find out if Singapore has any bilateral agreement with China on "Social Benefit" exemption so I have taken the worst case situation of having to pay China tax.
This 30,755 RMB works out to S$6,276 based on rough exchange rate of 4.9 RMB to S$1 (should use smaller figure to be more conservative thou).
This S$6,276 is WITHOUT any
CPF contribution. Meaning both the employer and employee contribution are given in net cash take-home pay.
This is equivalent to income from local employment with gross salary of $5,410 using 20% employee and 16% employee contribution rate.
So effectively, 50,000 RMB (S$10,204) base pay in China is equivalent to only S$5,410 base salary locally. In other words, the China local hire pay is inflated by 47%!
Also, you have no chance of seeing your "social benefit" contributions if you quit China within 15 years.
Food for thought for others who may also be considering a job offer in China. Just thought I would share since information is hard to piece together. Please correct me if any of the above assumptions etc are wrong.