Every year, the Washington, D.C.-based Tax Foundation calculates what it calls Tax Freedom Day.

That's the day, according to the tax research group, that Americans have finally earned enough money to pay their annual tax obligations at the federal, state and local levels.

April 18 is this year's Tax Freedom Day, five days later than in 2012.

There are several reasons, say Tax Foundation number crunchers, for the extra time needed to cover federal tax obligations.

Higher federal tax rates are now in place as part of the "fiscal cliff" legislation enacted in January's American Taxpayer Relief Act of 2012.

New taxes kick in this year as part of the continued rollout of health care reform.

And the economy is continuing to improve, meaning more workers are getting jobs and paying taxes on that income.

"The total tax bill at all levels comes to approximately $4.2 trillion, or 29.4 percent of their total income," said William McBride, a Tax Foundation economist, in announcing the date. "That means Americans will pay more in taxes in 2013 than they will spend on food, clothing and housing combined."

Since 1990, the group also has calculated each state's individual Tax Freedom Day.

Differing state tax policies mean that states with higher income rates celebrate Tax Freedom Day later.

Read more:

Happy Tax Freedom Day