One of the major inputs for retirement planning is how long you expect to live. Retirement calculators ask you to forecast your lifespan or number of years living in retirement. It’s a necessary input because longevity informs the estimated number of years your resources must last while paying your living expenses.

When I ask retirement-age people how long they expect to live, they frequently say something like, “I don’t think I am going to live very long”. Many people underestimate their longevity, perhaps because the older you are, the longer you are likely to live. Essentially, if something didn’t kill you when you were younger, you have a greater chance of living to an older age than a young person.

For example, a girl born today in the United States is projected to live, on average, to 86.9 years of age, according to the US Social Security Administration. However, once that woman reaches 67 years-old, she is expected to live until 90.2 years of age. Maybe 3.3 years doesn’t seem like a big deal, but it could be uncomfortable if there was no money to cover expenses for the additional time.  

Another important consideration is that the previous example considers only the expected average. However, there is a large range around the average. A 65-year old woman in the United States today can expect to live to age 86, but has a 33% chance of living to age 90, a 13% change of reaching 95, and a 3% chance of celebrating 100. Also consider that people who are healthier than average will likely live longer than average.

As tricky as it may be to correctly estimate the lifespan for one person, it is even harder to do correctly for one person out of a couple. Those numbers become relevant when a couple wants their retirement nest egg to last for the lifetime of the longest living survivor between them.

We did the math. There is about a 50% chance that one person of a female and male couple, both of whom are currently 65 years old), on average, will live until age 90. Even though men typically die earlier than women, the life expectancy for one person in a couple is longer than each of them individually by about 4 years! The chance that one person of the couple will reach age 95 is 20% and age 100 is 4%. As a result, healthy 65-year old couples should plan retirement funding at least through age 95.

As indicated earlier, projected longevity increases as the couple ages. That’s why the number of years to plan for living in retirement is a moving target and frequently underestimated. The data tables are posted below. One for men, one for women, and one for couples, showing the percentage chance of reaching age 66 through 100 for people who are now between the age of 65 and 99. For an even more precise estimate, use this longevity calculator developed by the American Academy of Actuaries and the Society of Actuaries. These tools can provide helpful perspective as you think about the number of years your resources need to last while living in retirement.