Understanding Divorce Rates in the U.S.: Terms, Formulas, and Lifetime Risk
When people talk about the divorce rate in the United States, they’re often referencing different statistics—each with its own method of calculation and meaning. Here’s a clear breakdown, thanks in part to Perplexity AI, of the most common ways divorce rates are measured today, the formulas behind them, and how experts estimate the lifetime risk of divorce.
Common Ways to Calculate Divorce Rates
1. The Crude Divorce Rate: Divorce Rate per 1,000 Women Age 15 and Over
A widely used measure in recent research is the number of divorces per 1,000 women age 15 and older. This group is used because it makes sense, compared to using the total population (which includes children and others who cannot divorce). See example at the bottom of this page.
Formula:
This method is used by the U.S. Census Bureau and many demographic studies, providing a picture of divorce trends among those who are actually at risk. See example at the bottom of this page.
2. Refined Divorce Rate (Per 1,000 Married Women)
For even greater precision, researchers often use the refined divorce rate, which measures the number of divorces per 1,000 married women in a given year. You cannot divorce if you were not married, right? I like this because people cannot critique the number, saying, “Well, the divorce rate is down because more people are cohabiting.” This excludes those who are cohabiting. And the figures are available for many decades. See example at the bottom of this post.
Formula:
This rate focuses solely on those currently married, offering a direct look at the risk of divorce among active marriages. For example, a rate of 14.9 per 1,000 married women means about 1.5% of married women divorce each year.
3. Lifetime Risk of Divorce Rate (Cohort or Cumulative)
If you’re interested in the likelihood that a marriage will end in divorce over a lifetime, you’re looking for the lifetime divorce risk (also called the cumulative or cohort divorce rate). This statistic estimates the proportion of marriages that will eventually end in divorce for a specific group of people marrying during a given period.
How is it calculated?
Demographers use a life table method, tracking a group of marriages over time and compiling the proportion that end in divorce at each year of marriage. By projecting these trends forward, they estimate the cumulative percentage of marriages expected to end in divorce. Researchers don’t use this very often, because it estimates the future rather than reporting the past.
Conceptual formula:
where is the maximum duration tracked (often 30–40 years).
What’s the current estimate?
In the U.S., the best current estimates suggest that about 42–45% of marriages will eventually end in divorce if current patterns continue. This is the figure most often quoted in discussions about the “lifetime risk” of divorce.
Summary Table
Why These Rates Matter
Understanding the differences between these rates helps clarify what’s really being measured. Divorce rates based on women age 15 and over, or on married women, provide a more accurate and meaningful snapshot of divorce trends than rates based on the total population. Meanwhile, the lifetime divorce risk offers a long-term perspective on the likelihood of divorce over the course of a marriage.
If you want to talk about the “chance” that a marriage will end in divorce, the lifetime divorce risk is the most meaningful statistic to use.
Some Examples and Links to Divorce Rate Calculations
Example of #1: Crude divorce rate (divorces per woman over 15, rather than the entire population which includes millions of children)
Example of #2: Refined divorce rate (divorces per married woman)
You cannot divorce if you were not married, right? I like this because people cannot critique the number, saying, “Well, the divorce rate is down because more people are cohabiting.” This excludes those who are cohabiting. This graph below starts in 1970 when the first no-fault divorce laws went into effect (California). For the next 14 years, more states passed no-fault divorce laws, and the spike in divorces in the late 1970s and early 1980s show a pent-up demand for divorces among those who couldn’t afford to hire expensive attorneys and conduct a long, expensive, criminal-style divorce case. Since that high from about 1978-1984, the divorce rate has been dropping. As of the most recent figures, the divorce rate is LOWER than it was in 1970, when the first no-fault laws went into effect. (No-fault divorce law did raise the divorce rate temporarily, but it also saved millions of lives. See link.)
https://www.bgsu.edu/ncfmr/resources/data/family-profiles/FP-24-26.html
Example #3: Lifetime Risk of Divorce Rate (In the U.S., the best current estimates suggest that about 42–45% of marriages will eventually end in divorce)
People always wonder about serial divorcers and whether they skew the figures higher. Yes, they do, but the vast majority of divorces every year are first divorces. Only about 3–5% of U.S. adults age 15 and older have been married three or more times.
Side note: Self-help Christian author Shaunti Feldhahn (often misspelled as Shaunti Feldhan) is wrong about her divorce rate stats. Feldhahn’s views are not taken seriously by anyone with credentials, not even the conservative pro-marriage pro-family organization, the Institute for Family Studies. They mention her by name in this linked article and say she’s not a social scientist and they don’t agree with her figures. Their article suggests the divorce rate is about 42%, not 20-25%.
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