How do your proportions compare?

The rule that arm span equals height is roughly true and remarkably useful — it is why Vitruvian Man works.

The measurement Unit

Almost exactly an arm span

1.75 m is longer than 5 of the 7 references on this page.

Reference figures are measurements and are rounded; the unit conversion behind them is exact.

Every reference on this page, with its size and its ratio to your number
Reference	Size	Yours ÷ theirs	Note
head height	0.23 m	7.61×	One-seventh to one-eighth of total height
foot length	0.26 m	6.73×	About 15% of height
forearm	0.26 m	6.73×	The original cubit
shoulder width	0.45 m	3.89×
leg length	0.83 m	2.11×	About 47% of height
arm span	1.75 m	1×	Very close to total height
total height	1.75 m	0.999×

Arm span is within about 2 cm of height for most people. Michael Phelps is a famous exception, with a span 8 cm longer.
A foot is about 15% of height, so shoe size really is a rough height predictor — but a very rough one.

Frequently asked

For most people, within a couple of centimetres. The ratio averages 1.00 in Europeans and slightly above 1 in people of West African descent.

About seven and a half in reality. Classical art uses eight because it looks more heroic, and fashion illustration uses nine.