Most Americans aren't saving enough for retirement, leading to big retirement-savings shortfalls. In fact, according to Employee Benefit Research Institute (EBRI), more than four in 10 families where the head of household is between the ages of 35 and 64 will run short of money during their retirement.

Not all households are equally short on cash for the future, though. In fact, EBRI found a shocking discrepancy between the projected retirement-savings shortfalls of older single women and those of older single men. The gender gap in retirement savings should concern everyone, but especially women -- who tend to be paid less than men, and who also tend to suffer career penalties if they choose to have children.

Older woman looking worried

Image source: Getty Images.

There's a huge gender gap in retirement readiness

According to EBRI, single women between the ages of 60 and 64 have an estimated retirement-savings shortfall of $62,127, while single men have a shortfall of $24,905. While both single men and single women are at risk of running out of cash during their golden years, obviously the risk is far greater for older women.

Widows, too, face a bigger risk of running out money than widowers, although the gap isn't nearly as extreme as the discrepancy between projected shortfalls for single men and those for single women. For widows, the projected retirement-savings shortfall is $15,782, while it's just $12,640 for widowers ages 60 to 64.

What can women do about the shortfall?

For women who have too little money saved as they near retirement age, working longer is one possible option. Women tend to have longer lifespans than men, so some could spend a few extra years in the workforce while still enjoying retirement for the same number of years. Working longer could allow women with a retirement-savings shortfall to set aside more money for the future. It could also result in higher Social Security benefits, as waiting to claim Social Security can increase each monthly benefit up to the age of 70.

For younger women who are still working, there are more steps that could be taken today to help reduce the retirement-savings shortfall. One of the most important is advocating for policies that close the gender pay gap. As long as working women make less than men in similar jobs, a retirement gender gap is likely to continue to exist. After all, it's harder to save as much for the future when your salary is smaller than those of your male counterparts.

Women also need to understand their rights, and speak up if they are being paid less than men for comparable work. This is a violation of federal civil rights laws, and women can take legal action. At the very least, they can talk with their bosses about bringing up their incomes to levels on par with male peers.

Studies have shown men are also more likely to negotiate their salaries than women, and more apt to apply for jobs they aren't 100% qualified for. When working women take a new job or begin a job search, they can adopt these techniques by not accepting the first offer they're made by an employer, and by applying for jobs that are a bit outside their comfort zone.

Advocating for family-friendly policies, such as paid parental leave and flextime, can also help both men and women to better balance the obligations of work and family. While things are becoming more equal, women still suffer a motherhood penalty that can affect their careers and, in turn, impact their ability to save for retirement.

Saving more for retirement is important for everyone

Ultimately, while increasing income and advocating for a more equal society would be the best way to solve the gender gap in retirement readiness, change is slow to come.

Women who want to make sure they have enough saved for retirement will simply need to make savings a priority, and budget to save at least 15% of income for their golden years. Of course, this is good advice for people of all genders, as the retirement-readiness gap affects everyone, even if it affects women more.

Saving this much for retirement can seem burdensome. But slowly increasing retirement-account contributions, and taking advantage of tax breaks for retirement savings, could help everyone make sure they don't fall short in funding their post-working years.