GTBuy Sizing Guide: Measure Before Choosing

Choose a size by comparing the live measurement chart with a similar item that fits; do not translate S, M, L or regional shoe labels without checking the seller’s actual measurements.

Build a personal reference

Measure an owned garment flat using the same points shown in the live chart: chest width, shoulder, length, sleeve, waist, rise or inseam. Write down whether a value is flat width or full circumference.

Shoes need more than a regional label

Foot length, insole length and internal shape are different measurements. Confirm which one a chart uses. A familiar US, UK or EU size can map differently across models, and extra insole length is not the same as foot length.

Allow for method and tolerance

Fabric tension, padding, curved surfaces and where the tape starts can change a measurement. Compare the seller method with yours and treat small differences as measurement uncertainty, not precision.

Category-specific dimensions

For bags, check width, height, depth, strap drop and opening. For eyewear, check lens width, bridge, temple length and total frame width. A marketing size name such as “medium” is not a substitute.

Verify the selected variant

A chart may cover several versions. Confirm that the live selection and the spreadsheet row use the same model, color, fit and size system before ordering.

Working checklist

• Measure a similar owned item.
• Match the measurement method.
• Confirm units and size system.
• Check the exact selected variant.
• Allow for stated tolerance if provided.
• Save the chart used for the decision.