Half Your Age Plus Seven Calculator
Works out the popular "half your age plus seven" rule for two adults. It is a social rule of thumb with no research behind it — not a legal limit, not a compatibility score, and not an ideal age gap.
Before you start
Method : arithmetic of a folk rule; inclusive bounds.
Checked : boundary cases (exactly on and just past each bound) tested.
Review : not independently reviewed by an expert or by the organisation whose rules are used.
Your entries stay in this browser tab; nothing is sent or stored.
How to Use This Calculator
- Enter your age (18+)
- Optionally enter another adult's age
- Press Calculate
Methodology & assumptions
Lower bound = age ÷ 2 + 7. Upper bound = (age − 7) × 2 (the same rule solved the other way). Bounds are inclusive and shown to one decimal; no rounding is used to decide inside/outside. Ages 18–120.
Worked examples
30: 22 to 46. A 22-year-old is inside; 21.9 is outside.
18: 16 to 22 — the lower bound is under 18, but the tool only accepts adult ages as input.
50: 32 to 86.
Understanding your result
Being "outside" the rule says nothing about whether a relationship is healthy, and being "inside" says nothing about legality or compatibility.
Sources & further reading
Frequently Asked Questions
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