What is the acceptable minimum age for your own (and others’) dating partners? When this question comes up in conversation, someone inevitably recites the “half your age plus seven” rule (detailed here). This rules states that by dividing your own age by two and then adding seven you can find the socially-acceptable minimum age of anyone you want to date. So if you’re a 24 year-old, you can feel free to be with anyone who is at least 19 (i.e., 12 + 7) but not someone who is 18.1 The lesser-applied other side of the rule defines a maximum age boundary. Take your age, minus 7, and double it. So for a 24-year old, the upper age limit would be 34 (i.e., 17 * 2). With some quick math, the rule provides a minimum and maximum partner age based on your actual age that you can use to be socially-acceptable in your dating decisions.
A Chart of the Rule's Max and Min Partner Age Discrepancies Based on a Person's Actual Age
The utility of this equation is that it lets you chart acceptable age discrepancies that adjust over the years. According to the rule, a 30 year-old should be with a partner of at least 22; whereas a 50-year-old’s dating partner must be at least 32 to not attract social sanction.
But how legit is this rule? Does it map on to our scientific understanding of age-related preferences for dating? Does it always apply?
How well does the rule reflect scientific evidence for age preferences?
Researchers Buunk and colleagues (2000) asked men and women to identify the ages they would consider when evaluating someone for relationships of different levels of involvement. People reported age preferences for marriage, a serious relationship, falling in love, casual sex, and sexual fantasies. Were they following “the rule”?
Based on the figures Buunk and colleagues (2000) provided (and thus the numbers are only informed approximations), I replotted their data superimposing the max and min age ranges defined by the half-your-age-plus-7 rule. Now we can see how well the rule corresponds with people’s reported acceptable ages.
Men’s preferred minimum partner age
Let’s start with minimum age preferences reported by heterosexual men. In Figure 1, the solid black line represents the rule’s calculation for minimum acceptable range. You can see that men are basically operating by the rule for minimum age preferences for marital relationships (blue bars) and serious dating relationships (yellow bars). Those age preferences consistently hover around the values denoted by the rule (the black line). If anything, in practice men are more conservative for marriage, preferring a minimum age higher than the rule would say is OK.
Figure 1: Male Participants' Minimum Preferred Partner Age as Compared to the Rule
When it comes to sexual fantasies, however, men have minimum age preferences that are younger than the rule would designate appropriate. For example, this sample of 60-year-old men report that it is acceptable to fantasize about women in their 20s, which the rule would not say is acceptable. But, fantasies are not subject to public scrutiny and the rule is only designed to calculate what is socially acceptable in the public eye. So this discrepancy is not a failure of the rule. For rule-related involvement (e.g., relationships), 60-year-old men are stating that the minimum acceptable age is around 40ish, which maps much more closely to the rule’s predictions.
Men’s preferred maximum partner age
The rule states that you can calculate maximum acceptable partner ages by subtracting seven from your own age and multiplying it by 2. Figure 2 clearly shows that the rule’s max-age guidelines for men do not reflect real-world preferences. The rule overestimates the perceived acceptability of men becoming involved with older women. Men do not show a linear increase in maximum age preference that matches the rule’s predictions. Instead, men report maximum acceptable partner ages that hover around their own age through their 40s. After 40, maximum age preferences for most categories remain lower than their own age. Thus the rule for maximum ages is fairly ineffective at capturing what men actually believe is acceptable.
Figure 2: Male Participants' Maximum Preferred Partner Age as Compared to the Rule
Case Study: George Clooney
Now let's apply the rule to actual dating behavior by examining George Clooney’s dating habits. George Clooney has been scrutinized at times for dating younger women, but not consistently, and this pattern is nicely reflected in a graph of his own age, his partners’ ages, and the rule’s calculations for minimum and maximum acceptable ages. Only twice has George Clooney become involved with women whose ages were outside the rule’s guideline (Celine Balitran and Sarah Larson). He walked the line with Elisabetta Canalis and Stacy Keibler but is well within the threshold in his current relationship with Amal Alamuddin.
Does the rule work for women?
The minimum rule (half-your-age-plus-seven) seems to work well for men, although the maximum rule falls short, failing to reflect empirical age-related preferences. How well does the rule capture women’s preferences?
Women’s preferred minimum partner age
Below are the data from Buunk et al.’s (2000) study on women’s minimum age preferences; the rule’s age calculations represented by the solid line. In general, the figure shows that women are reporting mimimum age preferences that exceed the rule’s predictions. In other words, while the rule states that 40-year-old women can feel comfortable dating 27-year-old men, this does not reflect the social preferences and standards of women. Women in their 40s think that 35ish or older is acceptable for marriage or a relationship. Even when fantasizing, women’s minimum age preference is over 30. The rule’s calculated minimum acceptabe ages seem to fit men better than women.
Figure 3: Female Participants' Minimum Preferred Partner Age as Compared to the Rule
Women’s preferred maximum partner age
Examining maximum preferences, again the rule is more lenient, offering an age range with which most people are not comfortable. The rule states that it is acceptable for 30-year old women to date men who are up to 46 years old, but in actuality, 30-year-old women state that their max acceptable partner age would be less than 40 (around 37ish). The rule underestimates women’s reported preferences in their 20s, but the gap between reports of what is socially acceptable and the rule itself widen over time.
Figure 4: Female Participants' Maximum Preferred Partner Age as Compared to the Rule
Case Study: Demi Moore
Let’s take a look at Demi Moore who at times has been criticized for dating men who differ substantially from her own age. As you can see from the graph, Freddy Moore exceeded the rule’s calculated acceptable maximum age, while Ashton Kutcher’s age fell short of the socially-acceptable minimum age when they first started dating in 2003. By the time of their separation in 2011 (and not shown in the graph), Kutcher at age 33 had crossed the threshold (31.5) defined by the rule.
How effective is the rule?
Curious outsiders are quick to judge when they can see an age gap between two romantic partners. Maybe this is why the rule is so appealing. In a world where social norms are often unspoken, the half-your-age-plus-7 rule concretely defines an age minimum boundary.
Indeed, the rule might be a handy rule-of-thumb but it does not map perfectly onto actual reports of what is socially-acceptable. At times the rule is too stringent, but most often the rule is too lenient, condoning age pairings with which most people would not be comfortable. So if you use the half-your-age-plus-7 rule, know that it may not be perfect and that it does not mirror age-related preference. Also, you might also take care to use the maximum age judiciously; the minimum age seems to work better and works best for men, not women.
1. No worries: hang on a couple years because when you’re 26, this person would be 20 and would be right at the line of your age-minimum threshold (13 + 7), and wait a few more years and you’ll be 28 and this person will be 22, above your new threshold of 21 (14+7).
Buunk, B. P., Dijkstra, P., Kenrick, D. T., & Warntjes, A. (2001). Age preferences for mates as related to gender, own age, and involvement level. Evolution and Human Behavior, 22, 241-250.