Just as US households start to see the benefits of tax reform in their paychecks, higher gas prices threaten to burn up at least a third of the spoils.

With the price of regular unleaded climbing 35 cents this year, to $2.84 nationally, the average road warrior — driving 15,291 miles per year — could see fuel costs increase by $216.

And that’s assuming her car gets 24.7 miles to the gallon. Households with less fuel-efficient vehicles will fare worse.

The sharp rise in gas prices comes as the new tax law — signed by President Trump in December — puts an extra $650 per year into the paychecks of the average US worker, according to a February report by the Institute of Taxation and Economic Policy.

For the average household, that means the higher gas prices will eat up a third of their tax benefit — assuming gas prices stay flat.

But with global demand staying strong and uncertainty about how sanctions on Iran will affect supply, Mark Zandi, chief economist of Moody’s Analytics, predicts that the price of gas will continue to increase and could consume as much as 50 percent the average household’s tax benefit this year.

“For every penny increase [in the price of gasoline] the cost to the American consumer is $1 billion,” Zandi told The Post.

And those effects are far worse for lower-income households, which spend a greater percentage of their income on gasoline. Making matters worse, lower-income households probably saw less of a paycheck boost from tax reform, Zandi explained.

“For that group, it might be a wash,” he added.