Glassdoor’s study on the gender pay gap is out, based on 505,000 salaries reported by full-time employees on Glassdoor.com. The study does two things: (1) It confirms that “The gender pay gap is real, both in the U.S. and around the world.” And (2) it confirms that using different data sets will result in different estimates of the gap. The overall gender wage gap in the U.S. is 24%, per Glasssdoor. But if you compare working men and women with similar ages, education and years of experience, Glassdoor pegs the gap at 19%. Further, comparing workers with the same job title, same employer and same location, the gender pay gap in the U.S. falls to just 5% — women earn 95 cents for every $1 paid to men.

5% may not seem like a lot. But over a lifetime of earnings, it is a big deal.

On a $50,000 salary, 5% is $2,500 a year. Put that $2,500 into savings each year at a 3% after-tax return. After 30 years you’d have close to $120,000 more for retirement. This is why we advise young women starting out in the workforce to realize there is a gender pay gap and to get comfortable researching and bargaining for salaries in their field.