Cost of living calculators are useless. For entertainment purposes only.
In the last 6 years I've lived in Ohio, Sarasota, FL, and now San Francisco. Two cross-country moves, in neither case was a cost of living calculator remotely relevant.
While I've never studied the calcualtors, I'd reason that they work by comparing median and mean prices from, perhaps, the consumer price index.
The trouble is that I don't buy Median $PRODUCT or live in median $HOUSING. And it doesn't cover the fact that at higher incomes I don't spend nearly all of what I make. And many of the things I do buy are consumer products that are the same everywhere: A MacBook or a Mercedes costs the same whether you make $60k as a programmer in Kansas or $120k in California.
And for housing, if I spend 50% above the median in Florida, that in no way suggests I'll spend 50% above the median in California. Maybe I'll rent a median flat in California that, due to a more expensive housing market, has many of the amenities I had to pay more for in Florida. Or I choose to accept a smaller house in California.
And for savings, while I now save a lower percentage of my California income than I was able to save of my Florida income, the absolute dollar amount is much higher now. And for retirement savings, I don't expect to retire in the highly-taxed California anyway.
The one area these calculators can get right is to set the appropriate expectation of tax differences.
In the last 6 years I've lived in Ohio, Sarasota, FL, and now San Francisco. Two cross-country moves, in neither case was a cost of living calculator remotely relevant.