How to Write a Shopify Sizing Guide That Explains What to Measure

A useful Shopify sizing guide tells shoppers what to measure, where to measure it, which units to record, and how to use the result with your verified chart. Its job is to make the chart understandable, not turn a measurement into a promise of fit.

Before drafting, gather the chart you intend to use, its approved measurement instructions, and any product-specific exceptions. Keep these together while you write. A polished paragraph should never introduce a sizing rule that the source material does not support.

1. Name the object being measured

Start the customer-facing guide by identifying exactly what the shopper needs to measure. Do not make them infer it from a heading such as Check your size.

The important distinction is between:

• Customer or body measurements: measurements taken from the person, following the method specified for that chart.
• Product dimensions: measurements of the item itself, taken using the specified product-measurement method.

These describe different things. A shared label such as chest does not, by itself, establish whether a chart describes a person or a garment.

Use only the approach applicable to your store’s chart. Your published guide does not need to teach both methods if shoppers only need one. If the chart’s measurement basis is unclear, resolve that before writing the instructions rather than silently treating body measurements and product dimensions as interchangeable.

2. Describe the measurement points in words

For each required measurement, explain where it starts, where it ends, and the path between those points. Use the same measurement name that appears in the chart so readers do not have to translate between your instructions and the table.

Build each instruction from the approved method:

• The identifiable starting point.
• The ending point, or return point for a measurement around an object.
• The route the measuring tool should follow.
• Any required tool, positioning, preparation, or product condition.

Include those details only where they are verified. Familiar advice about posture, stretching, flattening, or tape placement is not automatically appropriate for every product.

If you include a diagram, explain it in accompanying text. Match its labels and describe its actual measurement points and path. Measure as shown leaves the image doing all the work; the written instruction should remain understandable without it. Do not add dimensions or landmarks that the approved diagram does not establish.

3. Make the units explicit

State the unit before asking shoppers to record a result. Repeat it beside the result field and in the relevant measurement-column heading. A number without a unit is an unfinished instruction.

Use the units in your verified chart. If the chart provides more than one unit, keep those values clearly labelled and tell readers to use the matching column. Do not create an alternative size system or borrow a universal size-conversion table to fill a gap.

Keep size labels separate from measurement units: a size name identifies a chart entry; it does not explain what was measured.

4. Explain how to record the result

Give shoppers a separate place to record each required measurement, using its chart label and unit. Avoid vague labels such as measurement one when the chart uses a specific name.

Tell readers to retain the original reading. If your approved procedure requires a particular rounding or recording method, explain that method explicitly. If it does not, do not invent one to make the numbers look tidier.

Keep recording and size selection as separate steps. A shopper should be able to return to the original measurement when checking the chart, rather than finding only the size they initially guessed.

5. Walk through how to read the chart

The chart should not arrive at the end of the article with an instruction to choose accordingly. Explain the route from recorded measurement to chart entry:

1. Identify the applicable chart. State which product or product group it covers, including relevant variants where necessary.
2. Locate the matching measurement label and unit. Use the same wording throughout the guide and chart.
3. Check the recorded result against the listed values. Preserve whether the source gives individual values or ranges; do not rewrite one as the other.
4. Follow the approved selection rule. Where several measurements are required, explain how the chart says to use them together. Do not invent a priority between them.

Instructions such as choose the nearest size introduce a decision rule. Include them only when they are approved for that chart and product.

Describe a chart match as a chart match. Where the chart uses ranges, your measurement falls within this listed range explains what the numbers show. This will fit perfectly claims something more.

6. Give uncertain results a useful next step

Your guide needs a route for cases the chart does not clearly resolve. These may include a measurement outside the listed values, an unclear range boundary, different required measurements pointing to different entries, or uncertainty about a measurement point.

Use any verified exception or remeasurement instructions that apply. Otherwise, explain how shoppers can seek clarification through your store’s actual support route, if you offer one. Do not replace a missing rule with an automatic instruction to size up or down.

Make that request specific. Ask shoppers to identify the relevant product or variant, the chart they used, their measurement labels and units, and the step they could not resolve. This gives the question useful context without asking them to repeat the entire process in a message.

The next step should address the uncertainty: which chart applies, where to measure, or how an approved rule works. It should not promise that someone can guarantee fit from a number.

An unfilled sizing-instruction template

Use this template to assemble your instructions before turning them into customer-facing prose. Repeat the measurement fields for each measurement the chart requires. Complete every applicable field from approved material; leave gaps for clarification rather than filling them with generic sizing advice.

Instruction field	Approved content
Applicable product, product group, or variant	________
Object being measured	________
Source chart name and version, if applicable	________
Measurement label used in the chart	________
Measurement start point	________
Measurement end point or return point	________
Measurement path, tool, and required setup	________
Accompanying explanation of the diagram, if used	________
Measurement unit	________
Result-entry format and approved recording rule	________
How to use the recorded result in the source chart	________
Verified exceptions and their scope	________
Unresolved cases and approved next step	________
Merchant approval of every instruction	________

Approve the method, not just the wording

Before publishing, ask someone unfamiliar with the draft to identify the object, start and end points, unit, and applicable chart without extra explanation. Any hesitation shows you where the wording needs attention. Then check every instruction against the approved source, including chart labels, values, and exceptions.

SEOBoss can help turn verified store instructions into an editable Shopify article using your brief and store context. Keep it in the drafting role, not the sizing-calculator role. You still need to approve every measurement instruction and chart-reading rule.

Start with one verified chart and complete the template for it. The finished guide should leave shoppers knowing what to measure, how to interpret their result, and when to ask for clarification. That is a useful outcome without promising more than the chart can tell them.