For women, the life expectancy gap stands at 10.4 years.
Here's another way to think about that: Americans with fewer than 12 years of education have a life expectancy that's not much better than adults in the 1950s and 1960s. That tends to get masked by the overall increases in life expectancy the country has experienced.
The education disparity in life spans looks to have increased in recent decades. This paper shows that back in 1990 differences tended to be much smaller.
The size of the disparity does vary by race, too. Here's one chart from the paper that shows life expectancy for various levels of education, broken down by race and gender. The gaps between the most educated white men and women tend to be bigger than those of other racial backgrounds.
Part of this could be due to the direct impact of education on health. As these researchers note, other studies have shown education to have "direct beneficial effects on health through the adoption of healthier lifestyles, better ability to cope with stress, and more effective management of chronic diseases."
There are also some indirect effects. The unemployment rate for those with less than a high school diploma is nearly three times higher than that of Americans with bachelors degrees. Higher paying jobs tend to more likely come with health insurance coverage.
"The indirect effects of education through access to more privileged social position, better-paying jobs, and higher income are also profound," these researchers conclude. "The absence of education and its related socioeconomic status benefits exert their direct harmful effects throughout the relatively shorter lives of those in less fortunate social positions "