I work for a global company with offices in many countries. I am currently working in country A, but am being offered the possibility of transferring to an office in country B, which has a different currency and a much higher cost of living. How should I best go about negotiating a fair salary to maintain or improve my quality of life if I accept the offer?
It seems that I'm holding a few more cards than the typical salary negotiation process. First of all, I already have a job I'm happy in, which won't change if I decline the transfer - I'd be perfectly happy to stay put. Secondly, I'm being considered for the transfer personally due to my background and experience in the company, rather than hiring someone new. Third, HR will be coming to me with an initial offer, rather than the other way around. Finally, I have more experience than when I joined the company, so it might be possible to go for a raise rather than just an equivalent salary.
What are some good tools for determining an equivalent salary in a different country? Many of the cost-of-living calculators I've seen don't do international comparisons. For the ones that do, the fluctuating exchange rates make it difficult to know when the comparison was made, and what would be a true equivalent value at this particular point in time. Is it reasonable to use an average exchange rate over the past few years, or should all my calculations be based on the rate today, which happens to be near an all-time low? Or should I just ignore what I'm making now and just do research on the market value of my job in the area I'm potentially moving to?
EDIT: I'm actually currently working abroad, and the transfer would be a move back to my home country, so visas aren't an issue. I enjoyed a relocation package coming here in the first place, so I would expect something similar on the return.