Don't forget about taxes. Things cost 15% more, wages go up 20%, but the government takes a chunk of that 20%. Do you net even 15%? Depends on your tax bracket.

If wages go up 20%, your post tax income should also go up by approximately 20%.

The exceptions are if you enter a new tax bracket, but that only affects your marginal dollars, sns even then, the increase in tax brackets is just a few percent.

In the U.S., you could also cross the SS/Medicare threshold and then suddenly your post tax earnings will go up more than your wage increase.

Post-tax wage changes shouldn’t differ too much from the pre-tax wage increase.