Sizing is the single most common source of buyer dissatisfaction on OopBuy. The solution is simple: measure correctly and compare directly to the factory chart. This guide provides measurement techniques for every category, explains why factory sizing differs from retail, and gives specific advice for shoes, clothing, and accessories. Follow this guide, and your sizing accuracy will improve dramatically.
Why Factory Sizing Is Different
Factory sizing is based on Asian sizing standards, which are systematically smaller than US and European equivalents. A factory medium is often closer to a US small. The labels S, M, L, and XL are not standardized across factories. One factory's large might be another factory's medium. The only reliable measurement is the centimeter-based size chart. This is why measuring your best-fitting garment and comparing directly is the only method that works consistently.
Do Not Guess Your Size
Guessing your size based on what you normally wear has a failure rate above 50%. Measuring takes two minutes and prevents weeks of waiting for the wrong fit. Always measure first.
How to Measure Clothing
Lay your best-fitting garment flat on a hard surface. Use a flexible measuring tape. Measure chest width across the front, then double it. Measure shoulder width from seam to seam. Measure sleeve length from shoulder seam to cuff. Measure total length from shoulder to hem. Write these numbers down and compare directly to the factory chart. Do not convert or estimate. Use the exact numbers.
Clothing Measurement Steps
Lay Flat
Place garment on a hard, flat surface. Do not hang or drape it.
Measure Chest
Measure across the front, armpit to armpit, then double it.
Measure Shoulder
Measure from shoulder seam to shoulder seam across the back.
Measure Length
Measure from highest shoulder point to the bottom hem.
Compare to Chart
Match your numbers to the closest size on the factory chart.
Category-Specific Sizing Tips
Each category has unique sizing considerations. Shoes run 0.5 size small. Hoodies are often oversized by design. T-shirts vary by blank manufacturer. Pants have the highest return rate because buyers ignore inseam measurements. Jackets need sizing up for layering. Understanding these category-specific nuances before you order is essential for getting the right fit on the first try.
Category Sizing Guide
| Category | Sizing Tip | Common Error |
|---|---|---|
| Shoes | Measure foot length in cm | Using US size conversion tables |
| Hoodies | Check shoulder drop for oversized | Assuming standard fit |
| T-Shirts | Check length for tall buyers | Ignoring length measurement |
| Pants | Measure inseam and thigh | Using waist size only |
| Jackets | Size up for layering | Ordering TTS without room |
| Headwear | Check circumference | Assuming one size fits all |
Accessories and Non-Standard Sizing
Accessories also require sizing attention. Belts need your waist measurement plus 5-10cm for the tail end. Bags need dimension checks against your daily carry. Jewelry needs chain length verification. Socks are typically TTS but check the size range. Never assume accessories are one-size-fits-all without checking the measurements.
Create a Size Reference Sheet
Keep a note on your phone with your measurements for every category. When you find an item you want, compare instantly without remeasuring. This saves time and reduces ordering friction.
When to Size Up or Down
- Size up for layering pieces like jackets and hoodies
- Size down for oversized designs that run large intentionally
- Size up for wide feet or broad shoulders
- Size down for slim fits or athletic cuts
- Check stretch percentage for items with elastic materials