Half-Your-Age-Plus-Seven Calculator

Where the rule comes from

Half-your-age-plus-seven is a piece of folk wisdom that surfaces in old etiquette books and was popularised in 20th-century newspaper columns. The idea is symmetric: by the same formula, you also fall inside their acceptable range. It's a heuristic, not advice — and definitely not a legal standard.

How to use it

Type your age. The calculator returns the lowest age the rule considers acceptable for a partner (your age divided by 2 plus 7), the highest age (their age, halved plus 7, must still be ≤ your age — that simplifies to (you − 7) × 2), and the width of the range. The range gets wider with age — at 60, the rule allows partners from 37 to 106.

The math

Minimum partner age = your age ÷ 2 + 7. Maximum partner age = (your age − 7) × 2. The two formulas are mirror images: if you apply the minimum rule to a possible partner and ask the largest partner age that still keeps you inside their minimum, you get exactly (your age − 7) × 2.

Reference table

How the range opens up with age.

Your age	Minimum	Maximum	Range
20	17	26	9
25	19.5	36	16.5
30	22	46	24
35	24.5	56	31.5
40	27	66	39
50	32	86	54
60	37	106	69

Frequently asked questions

Is this a real rule?

It's a social rule of thumb, not a legal one. Age-of-consent and other laws are completely separate and vary by country and state.

Does the math actually mean anything?

Sociologists have looked at it as a model for perceived acceptability and found it lines up loosely with survey responses — especially for the lower bound. The upper bound is much more flexible in real-life judgments.

Why does the range get so wide at older ages?

Because both ends scale linearly with your age, but the upper end has a 2× multiplier and the lower end a 1⁄2 multiplier. The gap grows like 1.5 × (age − 14).

Is this dating advice?

No. It's a calculator for a piece of folklore. Real compatibility doesn't reduce to a single formula.

Why does it start at 14?

Below that age the formula returns ranges that include the user's own age (and below), which the rule was never designed for. We block it to keep things sensible.

What's the formula's earliest known appearance?

Variations show up in 19th-century French etiquette texts, then again in mid-20th-century English-language advice columns. It's old enough that no one really claims authorship.

Half-Your-Age-Plus-Seven Calculator