Two New Jersey and three New York City residents on Monday claimed Dunkin’ Donuts was clueless about sales tax.

A store in Ft. Lee, NJ, charged the state’s 7 percent sales tax on unsweetened bottled water and bags of ground coffee in clear violation of the law, a suit filed Monday in a New Jersey state court claimed.

A store near Manhattan’s Penn Station charged a customer sales tax on pre-packaged coffee beans — again in violation of state regulations, a second suit filed in federal court alleges.

“Dunkin’ should stop dunking their customers and provide customers with refunds or discounts so they are made whole,” lawyer Carl Mayer, who filed the suits, told The Post.

A dozen different Dunkin’ stores overcharged customers around 70 percent of the time, Mayer said.

As a result of the sales tax overcharges, Dunkin’ shops across New York and New Jersey made $10 million off New York customers and $4 million in New Jersey over three years, Mayer estimates.

Dunkin’ Donuts’ corporate office is in the process of reaching out to its franchisees to get to the bottom of the issue, according to spokeswoman Michelle King.