Compare net pay, not gross. Annualise over the actual number of payments. Convert at purchasing power rather than the exchange rate. Then list the statutory benefits separately instead of folding them into the number. Skipping any one of the four can reverse the answer, and most published comparisons skip at least three.
Step one: net, not gross
Marginal rates and the thresholds they apply at differ enormously between countries. A gross comparison between two different tax structures compares two quantities nobody receives, and the gap between gross and net can be twenty points wider in one country than the other.
Step two: annualise honestly
Establish whether the figure is monthly or annual, and over how many payments. Thirteenth and fourteenth month payments are common enough that assuming twelve is wrong often, and always wrong in the same direction.
Step three: purchasing power, not the exchange rate
The exchange rate tells you what your money buys if you convert it. Purchasing power parity tells you what you would need to buy the same things where you would be living. For a salary you intend to live on, only the second is relevant.
Step four: list what the salary does not have to cover
Healthcare, pension contributions and statutory leave, priced roughly and kept separate rather than folded in. Keeping them separate matters: it lets you see which part of the difference is cash and which is coverage, and those two are not interchangeable if you plan to leave.
What the four steps do not settle
Whether the qualification travels. Whether you can work there at all. What happens to the pension if you leave in three years. Whether your career in that country looks like your career here. Those regularly outweigh the arithmetic and none of them is in it.
The version most comparisons publish
Gross, converted at the market rate, over twelve months, benefits ignored. That is four errors compounding in the same direction, and it consistently flatters whichever country has the highest gross figures and the fewest statutory benefits.
Recognizing that pattern is most of what this section is for.
Common questions
What is the right order to compare in?
Net first, annualised over the actual number of payments, converted at purchasing power, with statutory benefits listed separately. Skipping any step can reverse the answer.
Why not just convert the gross figures?
Because gross is not a standard quantity across countries and the exchange rate answers a different question from the one you are asking. That is two errors before you start.
Why keep benefits separate rather than adding them in?
Because it lets you see which part of the difference is cash and which is coverage. Those are not interchangeable if you intend to leave, since coverage generally does not travel.
What do the four steps not tell me?
Whether your qualification travels, whether you can work there legally, what happens to a pension if you leave, and what your career looks like there. Those often outweigh the arithmetic.
Why do published comparisons get it wrong?
They typically use gross, at the market rate, over twelve months, ignoring benefits u2014 four errors compounding in the same direction, which flatters whichever country has high gross pay and few statutory benefits.