Date & time Age

Age gap calculator

From

Counting

Age gap —

The same gap in other units

Days —

Weeks —

Whole weeks —

Months —

Years —

Hours —

Minutes —

Note Enter both dates

Folklore, not research

An age gap is simply the difference between two birth dates. The half-your-age-plus-seven rule of thumb says the youngest socially acceptable partner is half your age plus seven — at 40 that is 27, and the oldest is 66.

How to use the age gap calculator

1 Enter two birth dates for the exact gap.

2 Or switch tabs and enter one age for the rule of thumb.

3 The rule gives both bounds from a single age.

4 Treat the rule as folklore, which is what it is.

The rule has no research behind it and appears in print as early as the nineteenth century as social advice rather than a finding. It has one interesting property: it is self-consistent, meaning if A is acceptable to B then B is acceptable to A, which is not true of most rules of thumb people invent. Below about age fourteen it produces a range narrower than a person, which is where its usefulness clearly ends.

Questions

What is the half your age plus seven rule? −

Divide your age by two and add seven for the youngest; reverse it for the oldest.

Is there research behind it? +

Is the rule symmetric? +

At what age does it stop making sense? +

Does an age gap change over time? +

Was this tool any good?

INTERNAL SIGNAL ONLY · WE USE IT TO FIND TOOLS WORTH REBUILDING