Women work more than men — but often, they're working for free.

A new report from the United Nations estimates women do 2.6 times the amount of unpaid care and domestic work that men do. Childcare, cooking and cleaning, even things like picking kids up from school or taking elderly parents to the doctor — these tasks disproportionately fall to women.

But women are not compensated for this work, and many national economies usually don't calculate it into a country's gross domestic product, or GDP.

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Shahra Razavi, chief of the research and data section at UN Women, says there's a reason this kind of "unpaid work" isn't calculated in GDP — because society still sees "women's work" as less valuable.

That is, if it sees it at all.

"If women stopped doing a lot of the work they do unpaid, then the whole economy would collapse," Razavi says.

In developing countries, work like finding fuel or gathering water often falls to women. Even in developed countries, domestic technology that once liberated so many housewives — appliances like dishwashers, laundry machines or even slow cookers — still isn't available to many poor women.

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According to the U.S. Department of Labor, American men spend more time than women exercising, playing games and enjoying other leisure activities. But all this unpaid work falling to women doesn't just mean women have less time to unwind. They also have less time to grow their careers.

Brigid Schulte, director of the Better Life Lab at New America, says the extra time that men have to research their fields and interests better prepares them for promotions and professional opportunities. Women, though, are strapped working a "second shift" of unpaid work at home.

"When you expect women to do all that unpaid work, they don't have the energy or the bandwidth to do that deep, concentrated work in the way that men do," Schulte says. "So that's robbing women of the ability to be innovators, for economics and companies and societies to take full advantage of women's talents."

Schulte points to two ways to lighten the unpaid workload women disproportionately bear.

First, companies and countries can institute family leave or flexible policies that help shift the cultural norms that keep men in the office and women in the home.

Second, families can discuss how this affects them on an individual level. Dividing the work not only eases family strife, it also sets an example for others to see how some couples can correct the imbalance.

"Even in countries where the division is so stark, there could be discussions about how to make things fairer," Schulte says.