Sales tax varies more by state than almost any other everyday cost, and the gap between the highest and lowest is bigger than most shoppers realize. California has the highest state-level sales tax rate in the country at 7.25%, with Indiana, Mississippi, Rhode Island, and Tennessee tied for second at 7% each. * Five states charge no statewide sales tax at all: Alaska, Delaware, Montana, New Hampshire, and Oregon. Of those five, only Alaska allows individual cities and counties to add their own local sales tax on top — so even in a "no sales tax" state, some Alaska purchases still carry tax at the local level. * The state-level number is only part of the real cost, though. Once you add in the average local sales tax on top of the state rate, the ranking shifts: Louisiana has the highest average combined state-and-local rate in the country at 10.13%, followed by Tennessee (9.61%), Washington (9.57%), Arkansas (9.48%), and Alabama (9.46%) — all considerably higher than California's combined rate, despite California having the higher state-level number. * Among states that do charge a statewide sales tax, Colorado has the lowest rate at just 2.9%, with Alabama, Georgia, Hawaii, New York, and Wyoming tied at 4% each — though in several of those states, particularly Alabama, hefty local sales taxes on top of the low state rate can still push the actual price you pay at checkout much higher than the base rate suggests. * Because local rates vary so much even within a single state, the combined averages here are useful for comparing states broadly, but they won't necessarily match the exact rate charged at a specific store in a specific city — check your local rate directly for an exact number.