What this table is comparing
Federal income tax and FICA are identical in every state, so they do not decide where your money goes — the state wage tax does. At a $75,000 salary the federal and FICA bill is the same in Wyoming as in Oregon; what changes is the state line underneath it. That is why the ranking is driven almost entirely by the eight states with no wage income tax (Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington) plus the low-rate states near the top.
Why the gap is bigger than it looks
A few thousand dollars a year is not a rounding error: it is a used car over five years, or a Roth IRA contribution every year. The table shows the gap in one column precisely because that is the number people never add up when comparing two job offers in two states — they compare the gross salary and stop.
What this does not include
This is a comparison of wage tax only, and it is deliberately simplified in two ways. State income tax is modelled as one effective rate on gross pay rather than the state's real brackets and deductions, and local or city income taxes (which matter in places like New York City, Philadelphia or Ohio municipalities) are not included. Neither are pre-tax deductions such as 401(k) contributions, health premiums or HSA contributions, all of which reduce taxable wages. Property tax, sales tax and the state's cost of living are separate decisions again — a state with no wage tax is not automatically cheaper to live in.
For an exact figure on one state, use the paycheck calculator with your own salary and filing status. The formulas behind both are documented on the methodology page.