April 18 marks National Tax Day around the country. But taxpayers may be paying more than they expected, not just from the IRS, but at the gas pump.

Americans are expected to pay $215 million in taxes on gasoline this year. Unknown to many motorists, the rising prices for gas have been attributed not just from the pumps, but from increased taxes that may drastically contribute on a federal and state level.

“While most Americans blame oil companies or gas stations for the high price of gasoline, few remember or are reminded by the portion Uncle Sam takes at the gas pump: 18.4 cents on every gallon,” Patrick De Haan, head of petroleum analysis at GasBuddy said.

De Haan continues by saying most states will often charge more than the federal amount and often don’t disclose how much tax is charged per gallon.

“Some states pinch motorists even more by having a percentage-based sales tax on gasoline, so that when gas prices rise, their coffers are filled at a faster pace,” De Haan said.

The top five lowest state gas taxes in the U.S. level out around 36.7 cents per gallon, with Alaska having the lowest gas price of 33.5 cents per gallon. Compared to the top five highest taxes averaging out to 76.2 cents per gallon with the highest gas tax in California with 86.55 cents per gallon.

GasBuddy warns drivers to be aware of gas tax changes when crossing state lines. Despite economic factors causing prices to increase, GasBuddy warns that even just raising the state and federal level by a penny would raise the consumer’s tax bill by $2.75 billion per year, according to a press release.