Joe Dominguez (author of Your Money or Your Life) tended to think that cost of living didn't necessarily track inflation. Is there any sort of calculator that might factor that in, or is CPI good enough?
I don't think there could be one for that, because it affects everyone differently based on their lifestyle and where they spend their money.
If it's important to you, you could track your expenses long term to find your own personal inflation rate versus CPI.
To me that's probably more of measuring with a micrometer and cutting with an axe, so while I think he's probably right, these rough numbers are good enough for me. YMMV.