Core answer: Measure three numbers — chest, waist, hips (in cm) — and match them to the garment's size chart, not the letter. Chinese standard builds: men's A-type = chest-waist difference 12–16 cm; women's A-type = 14–18 cm chest-waist. Pants: China size 31 = waist 2尺4 = 80 cm ≈ US 31 inches. Bra sizing: band (underbust) + cup (bust − underbust difference): 75B = 75 cm band, ~12.5 cm difference.
How to measure (2 minutes, once)
- Chest/bust: tape around the fullest point, level, breathing normally.
- Waist: natural waist (above the navel, where you bend), not where jeans ride.
- Hips: fullest point around the seat.
- Inseam: crotch to ankle bone on your best-fitting pants.
Write them in your phone's notes. Every future purchase is a lookup, not a gamble.
Women's dress size map (approximate — charts rule)
| China | US | UK | EU | Bust (cm) |
|---|---|---|---|---|
| 155/80A (S) | 2–4 | 6–8 | 34 | 80 |
| 160/84A (M) | 6–8 | 10 | 36–38 | 84 |
| 165/88A (L) | 10 | 12 | 40 | 88 |
| 170/92A (XL) | 12–14 | 14–16 | 42 | 92 |
Pants: the 尺码 conversion
| China (尺 waist) | Jeans size | Waist cm |
|---|---|---|
| 2尺1 | 28 | 70 |
| 2尺2 | 29 | 73 |
| 2尺3 | 30 | 77 |
| 2尺4 | 31 | 80 |
| 2尺5 | 32 | 83 |
| 2尺6 | 33 | 87 |
尺 × 33.33 = cm; jeans size ≈ cm ÷ 2.54 rounded.
Bra math (the most-returned garment for a reason)
Band = underbust rounded to nearest 5 (68–72 → 70). Cup = bust − underbust: 10 cm = A, 12.5 = B, 15 = C, 17.5 = D. Sister sizes share cup volume: 75B ≈ 70C ≈ 80A — if the band rides up, go down a band and up a cup.
Worked examples
Example 1 — Online blazer. Chest 94, waist 82 (差 12 = A-type edge, actually B-type): try 175/96B or size up and tailor the waist — shoulders can't be tailored, waists can.
Example 2 — Japanese brands. Japan runs ~1 size small: China M → Japan L. Check the chart's 身幅 (chest width) against your best shirt laid flat × 2.
Example 3 — Kids growth strategy. Child 118 cm: buy 130 with adjustable waist; sleeves roll, waists cinch, length lasts 2 seasons.
Common mistakes and myths
- Buying the letter, not the measurements — the same "L" spans 8 cm of chest between brands; the size chart is the only truth.
- Ignoring 体型 letters (Y/A/B/C) — two men both 175/92 can need A vs B; wrong build letter = tight waist with loose chest.
- Assuming free returns forever — platforms increasingly charge return shipping on apparel; measure once, return never.
- Shrinking surprises — untreated cotton shrinks 3–5%; "水洗棉/预缩" labels matter for exact fits.
- Bra band denial — 80% of support comes from the band; if it rides up your back, the cup can't compensate.