When creating humanoid races or species or just normal individuals, I sometimes want to describe a certain body measure and thus have to estimate a reasonable value. How do you do that? Are there algorithms, rules of thumb, charts, helpful 2D/3D modeling software?
Actual adult humans can vary considerably in height and weight. The ranges for healthy people are something like 1,50 m to 2,00 m and 50 kg to 100 kg, but with many outside these parameters that could still be considered healthy. The extremes for grown-up height (with dwarfism and giantism) are stunning 0,55 m (at 15 kg) and 2,72 m; normal-height people have weighed more than 440 kg. The body–mass index (weight divided by height squared) should be between 20 and 25 for normal-sized adults, but skinny and starving people could get towards 15 or below (as do kids) and there’s hardly an upper limit for obesity (beyond 100).
I could take tables for standard garment sizes which usually correlate height, (under)bust or chest girth and weight or hip circumference in a sex-specific way, but these only have certain measures and only for idealized standard bodies. Also, height differences there seem to be more important or common with men than women.
I know there’re 7½ and 8-head rules (from 4 for infants) when drawing human bodies proportionally, but again, that covers only certain parts – and I cannot draw well.
How to make a realistic 'giant' – is about people much taller than normal, 3+ m, and more about organs, shape and other implications.