Yeah, but I'm not moving from Detroit.
Here are the differences from Sacramento (where I currently live). I found this on another site similar to the one you used, but yours didn't have Sacramento in the list (these are based on the national average being 100):
San Francisco Sacramento, California
Overall 206 138.5
Food 121.4 120.3
Housing 348.6 181
Utilities 142.9 109.9
Transportation 129.1 113.3
Health 166.9 150.3
Miscellaneous 110 102.9
Food is barely any more expensive at all, housing is *WAY* more expensive, but I already mentioned that, utilities are more, but honestly, in shared housing, even paying 30% more for electricity/gas/whatever - it's like an extra $20-30 a month. Transportation is shown as more, but I can probably sell my car living in SF, depending on how often I need to drive it. In that case, it gets way cheaper for transportation in SF. If I keep the car, my insurance payments go up, yeah. Health care is more expensive, but work pays for that, so it doesn't matter. "Miscellaneous" is slightly more, but not that much.
Housing is the only big one I'm worried about. The others are relatively small increases, especially if I sell my car.
Even with housing, the calculator I was using said my current salary is equivalent to $55k in SF, which is still $13k less than I'll be making. Yeah, it might not be as big of an increase as it looks like from just the numbers, but it's still a significant increase, not to mention that I like SF way better than Sacramento, and I'd rather pay more to live somewhere I actually enjoy being.