If your workweek consists of only 40 hours, consider yourself lucky.

According to a recent Gallup poll, the average workweek in the U.S. is 47 hours, although Americans still think of 40 hours a week as "normal."

President Barack Obama's Affordable Care Act also defines full-time as 40 hours a week, despite the increase in hours four in 10 Americans are putting in.

The poll surveyed 1,271 adults from Aug. 7-10, scattered throughout all 50 states.

Gallup speculated in a news release that the increase in hours may be attributed to the way employees are paid.

"While hourly workers can face limits by employers trying to cut costs, those on a salary often work up to five hours a week more," reported Forbes. "Some people have also taken on a second job, contributing to time spent in the office."

Salary workers often put in extra hours during a workweek. The poll found that 25 percent of full-time employees on salary put in 60 or more hours a week.