Half Your Age Plus 7 Calculator
The half your age plus 7 rule says the youngest person you should date is half your age plus seven years. Enter your age or date of birth and this calculator gives that lower limit, the matching upper limit, and whether a specific partner falls inside the range. The upper limit comes from running the same formula backward: subtract seven from your age and double it.
For a 30 year old, the range runs from 22 to 46, and for a 40 year old it runs from 27 to 66. The range widens with age because half of a larger number moves further from the starting point. It is a social rule of thumb, not a law, and legal age limits always come first.
How to Use the Calculator
Type your current age or your date of birth, and the tool shows your minimum and maximum dating age under the rule. Add a second person's age or birthday to see whether the pair passes in both directions. A couple only fits the rule when each partner is within the other person's range.
The half your age plus 7 calculator also shows the year when an uneven pair will start to pass. Because the minimum rises by half a year for every year you age, the gap that fails at 25 can pass by 35. That timeline is often the most interesting part of the result.
The range widens with age
Shaded band: partner ages inside the rule. Dot: your own age. Scale 0 to 80.
The Formula Behind Half Your Age Plus 7
The minimum age equals your age divided by two, plus seven. The maximum age reverses the steps, so it equals two times your age minus 14. At 14 the formula gives your own age as the minimum, which is why the rule is meaningless for teenagers.
The table below shows the range for common ages. Anyone under 18 is outside the scope of this tool, and the rule never overrides the age of consent where you live. Values ending in .5 mean half a year, so 24.5 is 24 years and 6 months.
The same formula, run forward for the minimum and backward for the maximum.
| Your age | Youngest partner by the rule | Oldest partner by the rule |
|---|---|---|
| 22 | 18 | 30 |
| 25 | 19.5 | 36 |
| 28 | 21 | 42 |
| 30 | 22 | 46 |
| 35 | 24.5 | 56 |
| 40 | 27 | 66 |
| 45 | 29.5 | 76 |
| 50 | 32 | 86 |
| 55 | 34.5 | 96 |
| 60 | 37 | 106 |
| 70 | 42 | 126 |
Where the Rule Came From
The earliest well known version appears in the 1901 book Her Royal Highness Woman by the French writer Max O'Rell, who suggested a man should marry a woman half his age plus seven. Similar lines turned up in American newspapers in the following decades as a piece of folk advice. The idea was mostly forgotten until the internet revived it.
In 2007 the webcomic xkcd ran a strip called Dating Pools that used the formula and introduced it to a new generation. It has since become a standard reference in online threads about age gaps, often quoted to decide whether a celebrity couple is acceptable. The calculator on this page exists because people ask that question every day.
- 1901Max O’RellHer Royal Highness Woman
- Early 1900sUS newspapersFolk advice
- 2007xkcd, Dating PoolsRevived online
Is the Rule Accurate?
Research on stated preferences suggests the rule fits some people better than others. A 2001 study led by Bram Buunk found that the youngest age many men said they would accept for marriage was close to the half your age plus 7 limit, while women's stated limits followed a different pattern. In other words, the formula describes a social norm rather than a fixed truth.
The rule also ignores everything that makes a relationship work, such as shared goals and similar life stage. Two adults outside the range can be well matched, and two adults inside it can be at very different points in life. Use the result as a conversation starter and use the age difference calculator when you want the exact gap.
Frequently Asked Questions
What does half your age plus 7 mean?
It is a rule of thumb for the youngest person it is socially acceptable to date. You divide your age by two and add seven years. For a 36 year old, that gives a minimum of 25.
What is the maximum age under the rule?
Subtract seven from your age and double the result. A 30 year old gets an upper limit of 46. This is the same formula worked in reverse.
Does the rule apply to teenagers?
No, it breaks down below about 18 and should not be used for minors at all. Local age of consent laws decide what is legal, not a dating formula. The calculator only accepts adult ages for that reason.
Is half your age plus 7 a good rule?
It works as a rough guide to what many people consider socially normal, and little more. It says nothing about maturity, shared values or power imbalance, which matter far more. Treat a pass or a fail as one data point, not a verdict.
How old can a 25 year old date under the rule?
A 25 year old can date someone between 19.5 and 36 years old under the formula. In practice the lower end is usually rounded to 20, since nobody states their age as nineteen and a half. Both partners must pass the rule for the pair to fit it.