Just over a third of Americans, 36%, have a side hustle, according to a recent Bankrate survey of 2,332 U.S. adults, and they're bringing in significant amounts. On average, side hustlers are making an extra $891 per month.

And men and women alike are leaning in — 38% of men and 33% of women have one. Men, however, appear to be making considerably more. On average, men bring in $1,034 per month, while women bring in $735 per month.

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"It's definitely striking," says Laura Valle-Gutierrez, a fellow focused on economic policy at the progressive think tank The Century Foundation.

"The [side hustle] gender pay gap seems pretty similar to the full-time gender pay gap," she says. She attributes this to three main causes:

'The most common side hustles for women were child care and crafts'

Occupational segregation is the overrepresentation or underrepresentation of specific demographic groups in given fields. Often fields populated by women pay less.

This year, Bankrate's survey did not outline which kinds of side hustles people were doing, either in general or broken down by sex. But "the last time we asked about this," says Ted Rossman, senior industry analyst at Bankrate, "we found the most common side hustles for women were child care and crafts, and for men, it was landscaping and home repair."

Nationwide, babysitters make an average of $17.62 per hour, according to ZipRecruiter, while handymen make an average of $25.49 per hour.

'A side hustle is going to correlate to how many hours you can work'

Responsibilities in the home also play a part. Women are more likely to take on housework and child-care duties than men.

In more than half of households, 58%, women are more likely to do the laundry than men, according to a 2020 Gallup poll of mostly heterosexual married and cohabitating couples. Women are also more likely to clean the house (51% versus men's 9%), prepare the meals (51% versus men's 17%) and care for children on a daily basis (50% versus men's 7%).

"A side hustle is going to correlate to how many hours you can work," says Valle-Gutierrez, adding that, "if someone has more caregiving responsibilities, that's also going to be lowering the amount of income that they can generate on the side."

'A lot of the time, the woman set a lower rate for themselves'

Finally, women might be internalizing notions of their work's worth even in side gigs.

"If you look at studies that control for age, education, race, occupation," says Valle-Gutierrez, "looking within the same occupation and controlling for all those factors, there's still a wage gap." Women are getting paid less to do the same job. On average, women make 84 cents to a man's dollar, according to the National Women's Law Center.

"I see this all the time," says Kathy Kristof, founder and CEO of Sidehusl.com, adding, "go on any freelance platform where they set their own rates, and a lot of the time, the woman set a lower rate for themselves than the [male competition]."

Indeed, a cursory look at how much people charge for furniture assembly in New York on freelancer platform Taskrabbit reveals that while men often charge as much as $70 per hour, women don't charge more than $44 per hour.

'Don't undervalue your own work'

Though systemic issues require more than individual action, if you're a woman picking up a side hustle, Kristof offers a few tips.

First, "don't undervalue your own work," she says. "If you're setting a low price to build momentum, that's fine. But set a goal to raise your rates at a set point — say, after 25 five-star reviews."

Second, "find ways to magnify your income with technology," she says. If you teach, she suggests using platforms like Outschool where you can book multiple kids in one class. "Thus, while you may only earn $10 per student, you earn $100 an hour with 10 students."

Finally, lean into side gigs that pay. "Accounting, law, marketing, human resources, tech and other professional services pay professional rates" largely without regard to gender, she says. She suggests looking for part time work in like fields on sites like Robert Half, Catalant, Mayple and FlexProfessionals.

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