Pick someone's size without asking them

No print on either shirt here — a folded one, an open one, and a card of ranges next to a tape measure. Nothing about them is specific to a design.

That's the point. Sizing runs on the body underneath, and the body is something you can estimate without a single question.

Can I actually pick someone's size without asking?

Usually yes, from height and weight — or even a rough sense of both.

A size chart that publishes recommended height and weight ranges is handing you exactly that: two things you can judge about another person on sight, which is more than can be said for most sizing systems. Find those ranges on the product page and match the person to them.

Why does that work when a garment label wouldn't?

Because a letter isn't a measurement, and a body is.

"Medium" means whatever a given brand decided it means, and two mediums can differ by several centimetres across the chest. Height and weight aren't proxies for a size — they're closer to the thing the pattern was drawn around, which is why reading the chart from that direction is more reliable than reading the label.

Why does height track the shoulder and weight track the chest?

Because that's what each one physically determines on a person.

Shoulder width follows the skeleton, and height correlates with skeleton. Chest circumference follows mass, and weight correlates with mass. A tall lean person and a shorter heavier one can share a chest measurement and still need different shoulders — which is exactly the case a height-and-weight chart separates out and a single letter cannot.

Why is a shirt guessable when trousers aren't?

Because a shirt's fit is set by things you can see from across a room.

A waistband has to agree with an inseam and a rise, none of which are visible from outside somebody's clothes. A shirt needs an estimate of how tall a person is and roughly how they're built. That's why a shirt is one of the few garments it's reasonable to buy for someone else without consulting them.

What if my guess sits right on the edge of two sizes?

Then it probably is on the edge, and that's worth knowing rather than resolving arbitrarily.

Recommended bands are normally built to overlap, because a lot of people genuinely fit two sizes. A guess that lands between them isn't a failure of estimation — it's the chart admitting something true, and either answer is legitimate.

Does the cut make a wrong guess less costly?

Yes — a cut with ease built into the pattern is more forgiving than a fitted one.

Where the relaxed shape is part of the pattern rather than something achieved by rounding up, an estimate that's slightly off still tends to work. Guessing for a close-fitting garment is the harder version of this problem.

How do I get one made?

Describe the design at JustOG — a size guessed from height and weight is enough to start. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

You don't need their size. You need their height, and a guess at the rest.