In its earliest appearances, this rule is often cited as having French origins, although this citation always seems to appear in English-language (British or American) sources, leaving its true origin mysterious.
For convenience, the line representing x=y is also shown (in blue).
The area between the blue and red lines shows where you are the older partner in the half-age-plus-seven calculation, while the area between the black and blue lines shows where you are the younger partner.
The rule would theoretically create a paradox for people under 14, because the younger partner would have to be older than the older partner, but 14 is about the youngest you can be and make anything even remotely resembling adultish decisions respecting relationships anyway, so this rule works out rather well.
This has the advantage of allowing for a larger age gap the older the partners get; the four-year age gap between a 22-year-old and an 18-year-old is significant (and just barely allowed by this rule), but the same age gap between an 86-year-old and a 90-year-old isn't worth comment.
As Society Marched On, this became less and less the case, and in modern works a very small age gap is often considered ideal, with a maximum allowable (as opposed to "ideal") age gap proposed, and often applied equally in either direction (older man vs. One commonly-applied formula is the "half your age plus seven" rule, in which the older partner's age is divided by two and then increased by seven to reach either the ideal or minimum allowable age for a romantic partner.
Traditionally, a man was expected to be established in his career and lifestyle before marriage, whereas a woman usually transferred directly from her father's household to her husband's within a couple years of reaching adulthood, so it was considered ideal for the man to be at least somewhat older.Graph of the Half-age-plus-seven rule ("never date anyone under half your age plus 7"), which claims to dictate what age disparity between two people is acceptable in dating/romantic/intimate relationships during the late 20th century / early 21st century (called the "Standard creepiness rule" in the xkcd webcomic).According to this rule, the age of the younger person should not be less than half the age of the older person plus seven years, so that (for example) no one older than 65 should be in a relationship with anyone younger than 39 and a half, no one older than 22 should be in a relationship with anyone younger than 18, and no one under 14 years of age should be in a relationship at all...Downloading the excel file at A1-all.xls, we can continue the analysis and replicate Randall's findings.I edited the data found in the csv file to compute the age pools of singles by considering that the "single person" category is the union of the categories "Married Spouse Absent", "Widowed", "Divorced", "Separated" and "Never Married".A common rule of thumb, at least on the internet, is that it’s okay to be interested in someone “half your age plus seven” years.