The Four Sizing Systems
Shoes are labeled in US, UK, EU, and CM systems, and Chinese sellers sometimes mix them. US sizing is based on barleycorns and varies by gender. UK sizing is similar but one full size smaller than US men's. EU sizing uses the Paris point, which is two-thirds of a centimeter. CM sizing is the length of your foot in centimeters and is the most objective system.
The OSSBuy Spreadsheet standardizes all shoe listings to EU and CM to reduce confusion. When you see a listing with only US sizes, we add a conversion note in the community column.
Measurement Reference
Length: highest shoulder point to desired hem
Foot: heel to longest toe in centimeters
How to Measure Your Foot at Home
Place a blank sheet of paper on a hard floor against a wall. Stand on the paper with your heel touching the wall. Mark the longest point of your foot on the paper. Measure the distance from the wall edge to the mark in centimeters. Do this for both feet and use the larger measurement.
Add five to ten millimeters for toe room depending on the shoe type. Running shoes need more room than dress shoes. Sandals need almost none. Compare your final number to the CM column in the spreadsheet.
Measurement Reference
Foot: heel to longest toe in centimeters
Brand-Specific Sizing Quirks
Some Chinese brands run narrow. Others run short. The spreadsheet's fit notes column documents these quirks based on community feedback. A shoe marked true to size means it matches the CM chart exactly. Runs small means you should add half a size. Wide foot friendly means the toe box is generous.
When a seller uses their own custom size chart, trust the chart over the label size. We verify the custom charts against actual buyer measurements whenever possible.