How to Read Online Size Charts
— Flat vs Circumference
Open the garment size chart before the “recommended size” table. Match shoulder, chest, and length (or waist, hip, rise, inseam for pants) to your notes within about ±1–2 cm. Letters and height/weight suggestions are secondary.
Contents
- Why charts beat “recommended size”
- Tops — three numbers that matter
- Pants — four numbers that matter
- Flat vs circumference
- 60-second checkout checklist
- Review search words
- FAQ
1. Why charts beat “recommended size”
For a long time I bought straight off the height/weight suggestion table — “175 cm / 78 kg, so L.” The letter was usually right and the garment was still wrong in a way only I noticed: shoulders sitting off the bone, hems too long, pants that fit at the waist and failed at the thigh and rise.
The reason is simple. Every brand grades L to different centimetres, and the same brand splits its chart by season and by fit, so a slim L and an oversize L from one label aren't the same garment. Without your own measurement notes next to the listed garment specs, you're shopping on luck. I wrote up how this goes wrong specifically when you chase oversize in the 2XL oversize guide.
2. Tops — three numbers
| Field | What to compare | My habit |
|---|---|---|
| Shoulder | Shoulder width / across shoulder | ±1 cm; +2–3 cm only if I want oversize |
| Chest | Often half-chest on KR charts | Convert flat ↔ circumference before comparing |
| Length | Total length / body length | Too long shortens the leg line at 175 cm |
Sleeve length is worth checking when the chart lists it. When it doesn't, I look at the review photos instead and note where the cuff lands — wrist bone or over the back of the hand. If you don't have your shoulder number yet, start with measuring shoulder width alone, or with hand-span measuring if there's no tape in the house.
3. Pants — four numbers
| Field | Why | Fail pattern |
|---|---|---|
| Waist | Label 32 ≠ same cm everywhere | Waist OK, hip/thigh fail |
| Hip | Sitting stretch | Tight seat when you sit |
| Rise | Crotch comfort | Short rise digs or rides wrong |
| Inseam / length | Hem stacks or floats | Looks shorter even if waist fits |
The waist-fits-but-hip-and-thigh-don't pattern is the same one behind waist-to-hip ratio and the jeans gap and thick thighs and short rise. For which cut to reach for in the first place, see the pants silhouette guide.
4. Flat vs circumference
Korean charts usually list half-chest — the garment laid flat and measured across one side. So a “chest 55” is roughly 110 cm in circumference. US and EU charts more often give full circumference, which means comparing a Korean number directly against an imported one puts you off by a factor of two.
How I settle it before comparing anything:
- Look under or beside the chart for a note saying flat or circumference.
- If a top's chest number is in the mid-40s to low-60s, it's almost certainly flat.
- If your own note is a circumference, double the chart's flat figure before you compare.
5. 60-second checklist
- Your phone note has shoulder, chest and length — or waist, hip, rise and inseam for pants
- You compared like with like: flat against flat, circumference against circumference
- You're inside ±1–2 cm, with any deliberate oversize added on the shoulder only
- You treated the height/weight “recommended size” table as reference, not as the answer
- If you weren't sure, you left it in the cart and looked again a day later
6. Review search words
Rather than scanning five-star ratings, put these words into the review search box.
- Tops: shoulder, seam, length, sleeve, boxy, tight
- Pants: thigh, rise, inseam, gape, hip
The most useful reviews are the ones that give height, size bought and body part together — something like “175 cm, bought L, shoulders slightly wide.” One of those beats fifty reviews that only say the item is nice.
7. FAQ
Is a listed chest of 55 cm the circumference?
On most Korean charts it's half-chest, so the circumference is roughly double. Check the chart's own flat-versus-circumference note before you convert anything.
I usually wear L — can I just buy L?
There's no guarantee. L differs in centimetres between brands and between seasons at the same brand. Compare the actual measurements instead of the letter.
What if the listing has no size chart?
Use the model's height and size plus review keywords as a weak signal, and if you're still unsure, skip it or try it on in store. I almost never buy no-spec oversize items online.
What if I don't have a tape measure?
Build rough notes with the hand-span method first. You only need to correct them with a real tape once, before an order that actually matters.
I built a tool that runs this comparison for you. Save your numbers once in the size chart checker, type in what the listing says, and it handles the flat-to-circumference conversion and grades each field.
Disclaimer: Style and shopping education only. Not medical, diet, or growth advice. Garment measurements follow seller charts.