Sizing is the number one reason for returns in the MuleBuy spreadsheet. The problem is not that the items are poorly sized — it is that buyers do not know how to measure and compare correctly. In 2026, the sizing information in the spreadsheet is more detailed than ever, with flat measurements for every garment and insole measurements for every shoe batch. This guide is the complete resource for sizing. It covers how to measure, how to convert between sizing systems, how to read the spreadsheet charts, and how to account for batch-specific sizing quirks.
The Measurement Method
The only reliable way to get the right size is to measure a garment or shoe you already own that fits perfectly. Do not guess your size. Do not assume your standard size will work. The spreadsheet uses flat measurements, which means the garment is laid flat and measured across the front. For chest width, you measure across the front from armpit to armpit. For body length, you measure from the highest shoulder point to the hem. For shoes, you remove the insole and measure from heel to toe. These measurements are the foundation of every sizing decision in the spreadsheet.
How to Measure Any Garment
Shoe Sizing Conversion
Shoe sizing is the most complex because different batches use different lasts. The spreadsheet lists insole measurements in centimeters for most batches. This is the most reliable number because it is objective. US sizing is the least reliable because it varies by brand. Nike US 9 is not the same as Adidas US 9. European sizing is more consistent because it is based on the length of the last in Paris points. The conversion is roughly: EU size = (insole cm × 1.5) + 2. But the exact conversion depends on the batch. Always use the insole measurement as your primary reference.
Common Size Conversion Table
| US Men's | EU | UK | Insole (cm) |
|---|---|---|---|
| 7 | 40 | 6 | 25.0 |
| 8 | 41 | 7 | 26.0 |
| 9 | 42.5 | 8 | 27.0 |
| 10 | 44 | 9 | 28.0 |
| 11 | 45 | 10 | 29.0 |
| 12 | 46 | 11 | 30.0 |
Clothing Sizing by Category
Each clothing category has different sizing quirks. Hoodies and sweaters typically run oversized. A medium hoodie in the spreadsheet might fit like a large in fast fashion. T-shirts are usually true to size or slightly oversized. Vintage-washed items are pre-shrunk, so order your true size. Pants and shorts are the most precise category because waist and inseam measurements matter. Jackets are designed for layering, so size up if you plan to wear a hoodie underneath. The key is comparing the flat measurements to a garment you own, not guessing based on your standard size.
Category Sizing Behavior
Batch-Specific Sizing Quirks
Different batches from the same factory can have different sizing. This is because factories adjust their patterns over time. A batch from 2024 might fit differently from a batch from 2026. The spreadsheet notes batch-specific sizing quirks when they are known. The community also posts sizing feedback in QC threads. Before ordering, search for the batch code + sizing to see what other buyers report. If buyers consistently say a batch runs small, size up. If they say it runs large, size down. The community feedback is the most current and reliable sizing information.
Frequently Asked Questions
How do I measure the insole of a shoe?
Remove the insole from a shoe that fits well. Lay it flat and measure from the heel edge to the toe edge in centimeters. This is your reference measurement. Compare it to the insole measurement in the listing.
Do I need to size up for all clothing categories?
Not all. Hoodies and sweaters typically run oversized. T-shirts are usually true to size. Pants and shorts require precise measurement comparison. Always check the category-specific sizing notes in the listing.
What is the most reliable sizing system?
Flat measurements in centimeters are the most reliable. For shoes, insole length in centimeters is the best reference. For clothing, chest width, body length, and shoulder width are the key numbers. Avoid relying solely on S/M/L labels.
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