BBDBuy Sizing: Replace Size Conversion Guessing with Measurements

A generic rule such as “always size up once” is not a sizing system.

Different sellers can use different patterns and size charts.

Clothing: build a reference garment

Choose a similar item that already fits.

For a T-shirt:

• chest width;
• body length;
• shoulder;
• sleeve.

For trousers:

• waist;
• rise;
• inseam;
• leg opening.

For a jacket:

• chest;
• shoulder;
• sleeve;
• body length;
• layering room.

Measure flat

Use the same orientation as the seller chart when possible.

The goal is garment-to-garment comparison, not a generic body conversion.

Footwear

Use current seller sizing and foot-length guidance.

Do not assume every pair marked EU 43 has identical internal dimensions.

Oversized / slim / relaxed

These describe design intention, not exact dimensions.

Read the numbers.

Warehouse measurements

When an actual measurement photo is available, compare it with:

1. the seller chart;
2. the ordered size;
3. your reference garment.

Tolerance

Small manufacturing or manual-measurement differences can occur.

Focus on whether the difference meaningfully changes fit.

Keep a Personal Measurement Library

Save measurements from clothing and shoes that already fit you. A small reference table for T-shirts, hoodies, jackets, trousers and footwear is more reusable than repeated generic size conversions.

When a new listing appears, compare it with the relevant reference rather than with a country-size conversion chart.

Example: Why Letter Sizes Fail

Imagine two hoodies both labeled XL. One measures 62 cm across the chest and 66 cm long; the other measures 68 cm across and 73 cm long. The same letter produces a completely different silhouette.

This is why the useful comparison is not “What BBDBuy size am I?” It is “Which listed garment measurement is closest to the fit I want?”

Measurement Errors to Avoid

• comparing body circumference with flat garment width without noticing the difference;
• measuring a stretched elastic waistband and comparing it with a relaxed seller measurement;
• measuring a curved sleeve differently from the seller method;
• treating a one-centimeter manual difference as automatically serious;
• ignoring garment construction when two measurements look similar.

Use a Fit Tolerance, Not a Single Perfect Number

For each reference item, write an acceptable range rather than one exact measurement. For example, if your favorite tees are 58–60 cm wide, a listing at 59 cm is a straightforward comparison; a listing at 64 cm is a different fit decision rather than a “size conversion” problem.