If your chart only says “Chest: 54 cm”, customers first have to work out whether it means their body circumference or the width of a garment laid flat. Without that explanation, they cannot reliably use the value to choose a size, however tidy the table looks.
If it is a product measurement, the label might read “Chest width of the garment laid flat: 54 cm”. Customers still need an explanation of how to compare that measurement with their preferred fit.
Name body and product measurements explicitly
You can make the information clearer by explaining what each measurement refers to, how it is taken and its unit. A diagram can show the measurement points. For a product measurement, customers also need its condition, such as laid flat or fastened, because otherwise they may compare it with a different kind of value.
Do not copy a generic conversion from a different product. Cut, material and intended fit may differ. “True to size” needs a reference customers can understand. Use a substantiated description for this product alongside the appropriate measurements.
Baymard examines product-specific sizing guidance. Check whether a general size chart actually applies to the model being viewed.
Which measurements apply to your product?
Bringing the details together for one product and the sizes you actually offer shows which measurements are supported and where questions remain. An internal table might contain these columns:
| Field | What to record |
|---|---|
| Label | Inside length, circumference or width measured flat |
| Method | Start point, end point and product condition |
| Source | Manufacturer information or an approved measurement |
| Applicability | Product, model version and affected variants |
| Presentation | Unit, rounding and customer-facing explanation |
The source and model version remain internal; customers need to see the measurement method and unit. If a measurement is missing, refer it to the person responsible for the product before publishing the chart.
What happens between two sizes?
A boundary case needs a product-informed answer. When a measurement falls at the edge of a range, the recommendation may depend on material, use or preferred fit. Have the responsible product specialist establish the rule. “Size up if unsure” is not universal advice.
If your audience needs other units, conversion also requires a rule for rounding and accuracy. Values at the edge of a size range are worth checking again, because rounding could otherwise suggest a different size.
A support enquiry should be able to identify the specific variant. There is no need to send personal body measurements to analytics by default.
Check the guide within the shopping journey
You can check whether the guide supports selection with a participant who receives the necessary information but still has to find the appropriate size. Their route shows whether they discover the guide, understand the measurement and can explain their choice. Comparing the result with the cart then checks that the selected size is carried through correctly.
Test opening and closing the guide on a phone. Selection and scroll position should survive the return. Our existing Shopify product-page guide covers other aspects of product selection.
For a purchase-friction review, have the approved measurements and corresponding variants ready. We can then examine whether the guide supports size selection and define any subsequent CRO work.
