Size guide ecommerce pages need: what to include and where to show it

The short answer

A size guide ecommerce shoppers can use shows how to measure, a chart with the measurements for each size, fit notes such as whether a product runs small, and the sizing system it follows. Place it beside the size selector on every product page, built as text rather than an image, so it works on phones and can be read by search engines.

Why an ecommerce size guide earns its place

An ecommerce size guide does the job of a fitting room. Online, nobody can hold the product against themselves, so the page has to say how it will fit. When it does not, the shopper guesses, orders two sizes, or leaves for a shop that explains better.

The cost lands on you as returns: postage, handling and stock that cannot be resold at once. A clear guide is one of the more direct ways to reduce fit returns, because it works on every order without anyone on your team lifting a finger.

It will not fix everything. A guide cannot make a badly cut garment fit well, and it cannot correct sizes that vary from one batch to the next. What it can do is make the information honest, and honest information is what lets a shopper decide.

What a size guide should include

Most size guides fail by leaving something out, not by being too short. These are the parts shoppers look for.

• Instructions for taking each measurement, in one or two plain sentences, with a simple drawing where the point is easy to misread.
• A chart listing the measurements behind every size label, in both centimetres and inches.
• The sizing system the labels follow, such as US, UK, EU, AU or JP, with a conversion if you sell across borders.
• Fit notes for each product or range: slim, regular or relaxed, how much stretch the fabric has, and whether to size up when between two sizes.
• A statement of what the chart measures, the body or the finished product.
• The model's height and the size they are wearing in the photos.
• Care notes that affect fit, such as fabrics that shrink.
• A route to help for shoppers who are between sizes, such as a contact link or a summary of your returns terms.

Keep the order the same on every guide, so a shopper who has read one can find the answer in the next without rereading.

Body measurements or product measurements

Body charts tell the shopper which size suits their body. Product charts give the measurements of the finished item, so the shopper can lay a garment they already own beside the numbers. Each answers a different question, and mixing them on one chart is the most common source of confusion.

If you can only produce one, produce the product measurement chart. It is the one you can verify by putting a tape measure on a sample.

Build the chart as text, not as a picture

A size chart should be an HTML table, not a screenshot. Text can be read by screen readers, searched, resized and edited when a supplier changes a measurement. An image of a table does none of that. On a phone, a table that scrolls sideways with the size label fixed in the first column is easier to use than pinching to zoom into a picture.

Diagrams that show where to measure are fine as images, with alt text that says what they show. Put the numbers in the table and the picture beside it.

Check that the table is a real table to assistive technology: header cells for the size labels, and a caption that names the product range it covers.

Where the size guide should appear

Put the link beside the size selector, where the question arises. A text link reading Size guide, opening a panel over the product page, keeps the shopper's selected options and their place on the page. A link to a separate page makes them leave, and some do not come back.

On a phone, use a sheet or drawer with a close button that is easy to reach. Open it at the chart that applies to the product: women's shoes should not open the men's clothing chart.

Other places help as well.

• A short fit line in the product description, saying how the item sits and what size the model wears. The guide to writing product descriptions that sell covers how to word it.
• A general size guide page, linked from the footer and from category pages, where shoppers often look when comparing brands. The guide to building ecommerce category pages shows what else belongs there.
• Customer service replies and returns emails, which can link to the same page so answers stay consistent.

A separate size guide page can also be found in search. If you publish one, give it a clear title, link to it from products and check it against the usual problems listed in the ecommerce SEO audit guide, such as the same chart copied across many near-identical pages.

Write fit notes that match what customers report

Fit notes are only useful if they are true. Take them from your returns and reviews, not from the supplier's catalogue.

When a return is requested, ask for the reason from a short list: too small, too large, too tight in one place, looks different from the photos. Review the reasons per product each month. If a product keeps coming back as too small, say so on the page, in the same words every time: runs small, true to size, runs large. Add a fit question to your review form so later shoppers can see what earlier ones found.

Where one product line comes from several makers, a single chart will not cover them. Give each brand its own chart, or state plainly that the chart applies only to your own range.

Sizes, variants and product data

The size label in the selector, the chart and your product data should all agree. If the selector says M, the chart says Medium and the feed says 10, shoppers and systems are both confused. Pick one naming rule and apply it across the catalogue.

Product data for Google Shopping has its own fields. Google's Merchant Center documentation describes attributes for size, for size type (such as petite or tall) and for size system, which is the country whose sizing the label follows. Which products must supply them depends on the category and the country, so check the current documentation before you set up the feed. The guide to Google Shopping for online stores covers the wider setup.

Sizing outside clothing

Fit matters beyond fashion. Shoes need length and often width. Rings use size systems that differ by country. Furniture and appliances need dimensions and a note about doorways, stairs and lifts. Bedding, frames, helmets and bags are returned for the same reason: the shopper's picture of the size was wrong.

For these products, give dimensions in metric and imperial units, show an everyday object for scale in a photo, and put the measurement that matters most near the top of the page. A hand or a ruler beside the product tells a shopper more than a paragraph of description.

If you sell items in sizes on repeat, such as pack sizes or boxes for people of different builds, the size has to be captured when the shopper subscribes and be easy to change later. The guide to subscription products for online stores explains how recurring orders work.

How to build and test one

1. Collect the measurements from the maker, then measure a sample of each size yourself. Where the two disagree, trust your tape measure and tell the maker.
2. Decide whether the chart shows body or product measurements, and label it.
3. Write the measuring instructions and test them by asking someone who has not seen the chart to follow them.
4. Build the table as text, with metric and imperial values and the sizing system named.
5. Add the link beside the size selector and check it on a phone, with the panel opening at the right chart.
6. Review return reasons and fit reviews every month and update the fit notes.
7. Recheck the chart whenever a supplier, factory or cut changes.

Whether the panel, the size filters and the product data can all be done depends on your platform or custom build. If you are planning a store, the ecommerce solutions page describes what Liftup Technologies builds, and fit information is worth raising in the brief.

Related guides

• Ecommerce solutions
• Ecommerce category pages how to build them
• Ecommerce seo audit common problems
• How to write product descriptions that sell
• Ecommerce website vs mobile app for your store
• Website images how to size and compress

Questions and answers

Why do I need a size guide?

Shoppers cannot try a product on, so the guide takes the place of a fitting room. Without it they guess, order several sizes or leave. With it they have the facts to choose, which helps reduce returns caused by fit.

What should a size guide include?

It should include how to measure, a chart of the measurements for each size in centimetres and inches, the sizing system used, fit notes and the size the model wears. State whether the chart shows the body or the finished product. Add a way to ask for help.

Where should a size guide appear?

Place a link beside the size selector on every product page, opening a panel with the right chart for that product. A general guide page linked from the footer and category pages helps shoppers who are comparing brands.

Should a size chart be an image or a table?

Use a table. Text can be read by screen readers, found by search engines and edited quickly when a supplier changes a size. Keep images for diagrams that show where to measure, and give them alt text.

How do I handle different size systems in different countries?

Name the system the labels follow and give a conversion between the ones your customers use, such as US, UK, EU, AU and JP. Treat conversions as a guide, because brands differ. Say which label each product follows.

Do I need a size guide if I sell only one brand?

Usually yes. One brand still has different cuts across products, and shoppers do not know them. A chart for each range, with the range named, is enough.

Can a size guide stop all fit returns?

No. Some returns come from colour, quality or a change of mind. A guide targets the fit-related share, and you can see how well it works by comparing return reasons before and after you add it.