US Labor Department on published a long-awaited final rule Wednesday updating overtime regulations that will now allow millions of Americans to collect overtime wages.

The new rule raises the standard salary level from $23,660 a year to $47,476 for a full-year worker—meaning many salaried employees, administrators and professionals making under that threshold are now eligible to collect time-and-a-half pay when they work overtime. The Department of Labor estimates the new rule will immediately extend overtime protections to 4.2 million Americans and is expected to boost wages for workers by $12 billion over the next decade.

In 2014, President Obama signed a memorandum directing the Department of Labor to modernize the nation’s overtime rules, which have been comprehensively updated once since the 1970s. According to the administration the share of full-time workers who qualify for overtime based on their salaries has plummeted from 62 percent in 1975 to 7 percent today. The final rule also ensures an update to the salary threshold every three years.

The new rule will go into effect Dec. 1.