Macgi
Size advice for an online boutique is not just customer service—it is a fit-guessing process. The good news is that you can turn it into a simple, repeatable script so every chat, comment and DM uses the same questions, the same measurements, and the same way of recording the answer. This article gives you the questions, copy-paste replies, fit-note examples, and a way to track what you recommended so returns teach you something.
Start with the four questions that actually matter
Most size questions start and end with “What size are you?” That is not enough. A customer may say “M” because they wore M in a brand with generous sizing, or because they want an oversized look. Before you recommend, collect four types of information.
1. Height and weight
Height and weight are not perfect predictors of body shape, but they help you estimate whether a garment will be long enough, short enough, or too tight in the torso. The key is to ask politely.
Bad wording: “How much do you weigh?”
Better wording: “To recommend the best fit, may I ask your height and weight? I only use it to compare with our fit samples—like matching your measurements to a size chart.”
If the customer is uncomfortable sharing weight, ask for their usual bust, waist and hip measurements instead. Keep the tone practical, not personal.
2. Usual size in a known brand
Ask for a baseline. Different brands grade their sizes differently, so “I usually wear M” is more useful when you know which brand the customer is talking about.
Good question: “Which size do you usually wear in a brand that fits you well? For example, Uniqlo, Zara, Mango, H&M, or a local brand you love.”
For Vietnamese shops selling on Haravan, Sapo or Facebook/Zalo, you can mention Uniqlo or a common local brand the customer may know. The goal is to anchor your recommendation in something they already trust.
3. Fit preference
The same garment can fit one customer as a slim look and another as a relaxed look. Always ask how the customer wants it to fit.
Question: “This style is designed to be relaxed. Do you want it fitted, regular or loose?”
If the product is meant to be oversized, say so. If it is cropped, say where it is supposed to end. That prevents the customer from choosing a size based on an entirely different expectation.
4. Measurements from a garment they already own
The most reliable method is to compare the product to a similar garment the customer already owns and likes. Ask them to measure that garment flat.
Script: “Do you have a top/dress/pair of trousers at home that fits you the way you want? If yes, can you lay it flat and measure the chest, waist and length in centimetres? I can compare those numbers with our size guide.”
This works better than asking for body measurements because most people do not know their exact body measurements, but they have a favourite item that fits.
Photo: MART PRODUCTION / Pexels
Turn garment measurements into a size recommendation
Once you have the customer’s information, you need a reliable way to compare it with your products. This is where garment measurements and fit notes do the hard work.
How to measure a garment flat
Create a measurement guide for your team and your customers. For tops and dresses, measure:
- Chest: across the garment from underarm to underarm, then double it.
- Waist: across the narrowest part, then double it.
- Hip: across the fullest part, then double it.
- Length: from the highest point of the shoulder or waistband to the bottom edge.
- Sleeve: from the shoulder seam to the cuff, or from the centre back for long sleeves.
For bottoms, measure waist flat, hip flat, thigh flat if possible, inseam, and rise. Keep a Google Sheet or an internal page with these numbers for every SKU.
Use a worked example
Suppose a customer says her bust is 94 cm and she wants a regular fit. Your product page says the size M top has a 52 cm flat chest. Double that to get approximately 104 cm around. That gives about 10 cm of ease, which is usually a relaxed fit. If she wants a closer fit, size S might be closer but you should check the waist and shoulder too.
This arithmetic is simple, but it only works if your flat measurements are consistent. If two team members measure differently, the advice will be wrong. Create one measurement method and stick to it.
Write fit notes that reduce guessing
Most shops write “true to size” or “runs small”. Those phrases are not helpful because every customer defines them differently. Replace them with specific notes.
Good fit note: “Model is 168 cm, wearing size M. This knit has 5% elastane, so it stretches about 3–5 cm in the chest. If you are between sizes and want a close fit, choose the smaller size.”
Bad fit note: “Runs large. Size down if between sizes.” The customer still does not know how large, at what point, or which body parts are affected.
Add fit notes to each product page in the description, a “Size & fit” tab, or a collapsible section. For Shopify and WooCommerce, you can put this in the product description or use a custom tab. For Haravan and Sapo, use the product description field or a size guide page.
Scripts and checklists for chat and comments
Here are copy-paste scripts you can adapt for Facebook, TikTok, Zalo, Instagram DMs, or your website chat. The goal is to move the conversation from “what size?” to a real recommendation in a few steps.
First reply when a customer asks “What size should I get?”
“Happy to help! To suggest the best size, can you tell me:
- Your height and weight, or your usual bust/waist/hip measurements.
- Which size you usually wear in a brand that fits you well.
- Whether you want a fitted, regular or relaxed look.
If you have a similar item at home, you can also lay it flat and measure the chest, waist and length—I can compare it with our size guide.”
This reply works in chat and comments. In a public comment, add: “I’ll send you a private message so we can talk measurements without sharing personal details here.”
When the customer says “I’m usually M”
Do not just answer “Then take M.” Ask for the brand.
“Which brand is that? We can match that size to ours better. Also, this style is designed to be relaxed/fitted. Do you want that kind of fit, or a different look?”
If they cannot name a brand, ask for a garment measurement instead.
When the customer is between sizes
“You are right between sizes. Here is how to decide: if you want a closer fit, take the smaller size; if you want more room or plan to wear a thicker layer underneath, take the larger size. The model is 165 cm and wears size S with a fitted look. If your chest/hip measurement is closer to ___, choose ___.”
Fill in the blanks from your product data. This turns a vague “size up or down” into a specific comparison.
When the customer gives measurements
“Thank you! Based on your measurements and the fit you want, I recommend size ___. The flat chest of this size is ___ cm, waist ___ cm, length ___ cm. That should give you a ___ fit. If you prefer a looser/more tailored look, size ___ may be better.”
Use the examples above. If you are not sure, say so:
“Your measurements fall between two sizes and the fabric has limited stretch. I would lean toward ___, but if you prefer a roomier fit, choose ___. We can note this on your order so returns are easier.”
Quick comment reply for social media
For a Facebook or TikTok comment, keep the public reply short:
“Hi! It depends on your height, usual size and how you want it to fit. I’ll send you a message to help you choose.”
Then move the conversation to DM and use the first script. This keeps personal details private and keeps your comment section useful for other shoppers.
Photo: Ron Lach / Pexels
Use try-on images and model photos the right way
Written advice helps, but customers also want to see the garment on a body. Use try-on images deliberately.
Show the same garment on more than one body type
If possible, photograph the same product on models with different heights, bust/hip proportions and sizes. Add a caption under each photo: “Model A: 168 cm, bust 86 cm, wearing S. Model B: 160 cm, bust 94 cm, wearing M.”
This is more useful than one studio shot. It lets a customer mentally compare herself to a model instead of guessing.
Keep the product images accurate
If your product images are heavily retouched, the size conversation becomes harder. The customer may receive an item that looks different from the photo and blame the fit advice. Use lighting and background cleanup carefully, but do not change the actual garment shape, fabric weight or seam positions. For more on this, see AI Product Photography for Clothing: Keep Product Shots Accurate.
Use short try-on videos
A 10-second video of a model turning to the side and lifting her arms can show how the fabric moves, where the hem falls, and whether it clings. This reduces the need for customers to imagine the fit from a flat photo.
When you have a virtual try-on option
If your product page has a try-on button next to “Add to cart,” point the customer to it after the chat. It can confirm the visual look on their own body shape before they buy. If you do not have one yet, model photos and garment measurements are your fallback.
Record the advice so returns teach you something
Many boutiques give good size advice but never record it. Then the same fit issue repeats. Create a simple system.
What to record
For every size consultation, note:
- Date and platform (Facebook, Zalo, web chat, email).
- Customer name or order number.
- Which product they asked about.
- Their answers: height, weight or measurements, usual brand and size, fit preference, garment measurements.
- Your recommendation.
- The size they purchased.
- Whether they returned or exchanged, and the return reason if known.
- Any follow-up needed.
A spreadsheet works, but order notes are better because they stay with the order.
Where to record it on common platforms
- Shopify: open the order in admin, scroll to the order timeline, and add a note. You can also add a customer note in the customer profile, or add a tag like
size-advice-givenorbetween-sizes. - WooCommerce: open the order in WordPress admin and use the order notes panel. You can add a private note or a customer note if you need to send it to the shopper.
- Haravan and Sapo: use the order or customer note field in the admin. If your platform does not have a custom field, keep a shared spreadsheet and paste the order ID.
- For Instagram/TikTok and Zalo DMs, record the chat after the order is placed.
Review your notes monthly
At the end of each month, filter orders where size advice was given and look at returns. If a particular style has many returns from customers who were between sizes, add a fit note: “This style runs small at the shoulder; if between sizes, choose the larger size.” If a question is missing often, update your chat script.
This turns returns from a loss into training data for your next conversation.
Build a size guide from repeated answers
Once you have recorded enough advice, build a reusable size guide so you do not have to answer the same question from scratch every time.
Create a page or a product tab with:
- A size chart with garment measurements for every size.
- Fit notes for each style: “fitted,” “relaxed,” “stretchy,” “cropped.”
- Model details for each product.
- A short “how to measure” photo or video.
- The four questions from this article, so customers can self-serve before contacting you.
On Shopify and WooCommerce, you can create a page and link it in the main menu or add it to a product description. On Haravan and Sapo, create a size guide page and link it from the product description or a banner. Update it quarterly as your product range changes.
If you sell kids’ clothing, add age and height guidance as well. For help with that, see Kids Clothing Size Chart: Age, Height, Weight and Growth Room.
When a customer has a clear fit question, start with the guide, then use the chat script only when they still need help. This saves time and makes your advice more consistent.
Try-on images can close the last gap before checkout
After all the measurements and scripts, the customer still wants to see herself in the garment. That is why a virtual try-on button on the product page can help: it lets shoppers judge the look on their own photo before they buy, using your existing product images. Macgi makes a lightweight virtual try-on widget that sits next to “Add to cart” and works on WooCommerce, Shopify, Haravan, Sapo and custom sites. If you want to add this to your size-advice process, try Macgi’s widget in the free beta.
FAQ
How do I ask for weight without offending the customer?
Focus on fit, not body. Say: “To suggest the best size, may I ask your height and weight? It helps me compare with our fit samples.” Offer body measurements or garment measurements as an alternative.
What if the customer refuses to measure a garment at home?
Use height, weight, usual brand and fit preference. If you are still unsure, give a range: “Size M will be more fitted, size L more relaxed. Which look do you prefer?”
Should I record every chat size conversation?
Record every conversation that ends in a recommendation, especially if the customer places an order. Even a short note like “recommended M, customer usually S in Uniqlo” helps when the order comes back.
How many questions are too many?
Four are enough: height/weight or body measurements, usual brand and size, fit preference, and a garment measurement if possible. Do not ask for more than that in a first reply.
Which fit note is more useful: “true to size” or specific measurements?
Specific measurements and model details are more useful. “True to size” does not tell the customer whether the garment will fit their shoulders, bust or hips.
Can I use the same scripts for Vietnamese and international customers?
Yes. Keep the questions the same. For Vietnamese customers, mention Uniqlo or a local brand they know, and use centimetres. For international customers, you can mention common global brands and offer inches if needed.
