Miami is 22% more expensive than St. Petersburg.
When comparing Miami, FL and St. Petersburg, FL, the overall cost of living indices are 129 and 106 respectively (national median = 100). Rent is $115/month cheaper in St. Petersburg, saving renters about $1,380/year.
Median household income is $13,728/year higher in St. Petersburg. Home values also differ significantly — the median in Miami is $475,200 compared to $331,500 in St. Petersburg.
Both cities share the same state tax structure since they are in Florida.
Miami vs St. Petersburg — common questions
Other cost of living comparisons for Miami and St. Petersburg