A size guide becomes answers shoppers trust when it is written as text a chatbot can read, with each size stated in full on its own line and the fit advice the chart leaves out written down beside it. Most size guides fail here for a mechanical reason: they are images or pop-ups the bot can't see. Fix the format, add a few fit notes, and "what size should I get?" gets a specific, sourced reply.
This guide is about the structure of the size guide itself. For why sizing questions drive returns in the first place, read how chatbots reduce product returns with sizing, fit and spec answers.
Why most size guides are invisible to a chatbot
A website crawler reads the text of your pages. SpideyChat's crawler, for instance, fetches each page's HTML, keeps the readable text and drops scripts, images, embedded frames and the header, footer, navigation and sidebar areas. That is the right behaviour for most pages, and it causes three common size guide failures:
- The chart is an image. A JPEG of a table has no text in it. The bot can't read a single number.
- The chart lives in a pop-up loaded by a script. If the size guide only appears when someone clicks "Size guide" and it is fetched by JavaScript, it often isn't in the page's HTML at all.
- The chart sits in a sidebar or footer block. Theme areas marked as asides or footers are skipped as navigation.
The test is simple. Open the page, select all the text and paste it into a plain text editor. If the measurements aren't there, the bot can't see them either.
The fix: publish a dedicated size guide page with the chart as an HTML table or as written lines, and link it from product pages. If your guide is a PDF, upload it as a document instead, as long as it contains real text. A scanned PDF is just another picture.
Write one size per line, with units
Even a readable table can produce muddled answers. To answer a question, the bot searches your content for the passages closest to it, and long pages are cut into smaller pieces first. In SpideyChat those pieces are about a thousand characters each. A big chart can be split so that a row like "M 96 81 104" lands in a piece without the header that says which number is the chest.
Write it so every line stands on its own:
Women's tops, UK sizing, body measurements in cm. Size S (UK 8 to 10): bust 84 to 89, waist 66 to 71. Size M (UK 12 to 14): bust 94 to 99, waist 76 to 81. Size L (UK 16 to 18): bust 104 to 109, waist 86 to 91.
Four rules make this work:
- Name the product range on every chart. "Women's tops" and "men's trousers" should never share an unlabelled table.
- Say whether measurements are body or garment. A 96 cm garment chest and a 96 cm body chest are different sizes.
- Give the unit, and both units if you sell abroad. Inches and centimetres on the same line avoid conversion guesses.
- Use ranges, not single numbers. People sit between numbers, and a range tells the bot which size to name.
The numbers above are a hypothetical example layout, not a recommended chart. Use your own measurements.
Add the fit notes charts leave out
Charts answer "which size is a 96 cm chest?". Shoppers mostly ask something else:
| What they ask | What you need to have written down |
|---|---|
| "Does this run small?" | A fit note per style: true to size, slim, relaxed, or size up |
| "I'm between sizes" | A house rule: size up for a looser fit, down for a closer one, or style specific |
| "Is it stretchy?" | Fabric and stretch, in plain words |
| "What size is the model wearing?" | Model height and size, in the product description |
| "Will it shrink?" | Care instructions and expected shrinkage, if any |
| "Is it the same as your other jeans?" | How fits compare across your ranges |
These notes belong on the product page or the size guide page, in sentences. A line such as "The Harbour jumper is a relaxed fit; if you're between sizes, take the smaller one" gives the bot something exact to repeat.
For awkward facts that don't fit naturally on a page, add a Q&A pair. A question like "Do the Harbour jeans run small?" with your exact answer is quick to add and easy to edit later.
Tell the bot how careful to be
A good sizing reply quotes the chart, adds the fit note and admits what it can't know. Put the rules in your chatbot's instructions. In SpideyChat that is the "System prompt (persona & instructions)" field:
For sizing questions, use the size guide and the product's fit notes only. Ask for the shopper's measurement if they haven't given one. Say which size it falls into, mention any fit note for that style, and if they are between sizes, give our between-sizes rule. Never promise a fit, and suggest measuring with a soft tape if they are guessing.
Here is how that sounds in practice, for an imaginary knitwear shop:
Shopper: I'm usually a 12, which size in the Harbour jumper? Bot: A UK 12 is our size M, for a bust of 94 to 99 cm. The Harbour is a relaxed fit, so if you're between sizes we suggest the smaller one. If you have a tape measure handy, a quick bust measurement will confirm it.
The answer is specific, comes from your own content, and doesn't pretend to see the shopper.
Keep it current and check the misses
Size guides change with new ranges and new suppliers. When yours changes, re-crawl the page (website crawling is on Starter and above) or re-upload the document, and delete the old version so two charts don't disagree. Our guide on which pages your chatbot should learn from covers pruning outdated pages.
Then read the questions the bot couldn't answer. SpideyChat lists them as knowledge gaps, including replies a shopper marked unhelpful. Repeated gaps such as "what's the inside leg on the tall fit?" point to a measurement your guide never mentions. The training documentation covers each way of adding content.
To see whether your current size guide is readable, run your store through the free test and ask a sizing question for one of your best sellers. If the answer is vague or missing, start with the paste test above.