Size Calculation
Your customers stop guessing their size
Size Calculation puts a QR code on your product page. The shopper measures with their own phone, confirms once, and you get real measurements in centimetres.
The size comes from your own garment chart — not a generic EU/UK/US table.
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▸ One script tag on the product page
▸ The shopper confirms every transfer
▸ Raw scan data never leaves their phone
Mercan Atölye · Ball skirt
Why do size charts still get the size wrong?
A size chart describes the garment, not the body standing in front of it. To use one properly the shopper needs a tape measure they usually do not own, and someone to hold it. So they skip it and guess — and a guess is what fills the returns shelf, twice: once when the wrong size ships, and again when the replacement misses too.
Every "helpful" question a shop adds — gender, fit, usual brand, size system — just moves the guess somewhere else. The shopper still has to translate their body into a number nobody measured.
Size Calculation measures the body, then reads your chart
Size Calculation never asks the shopper for gender, fit, brand or size system. The app measures the body with the phone's own camera, and the size is looked up in the chart you uploaded for that exact garment.
Real distances, not photo guesses
On a Pro iPhone the LiDAR scanner measures true distance. On every other phone the app asks the shopper's height once and scales the body silhouette from it, cross-checked against the floor the phone tracks. Either way the shopper stands facing the camera, then turns 90 degrees, arms relaxed at the sides — under two minutes, and the same measurement engine on both platforms.
Your chart decides the size
You open a garment in the panel and give it a size chart, a gender and a fit rule — including "runs slim, also suggest one size up". The QR on that product page is born for that garment, so the recommendation is yours, not an average of the market.
Two ways to receive the data
Pull the confirmed measurements from the API when you want them, or let Size Calculation push them to your endpoint as an HMAC-signed webhook. Both are managed from the same panel, and you can run both at once.
A privacy story that survives scrutiny
Camera frames and depth data never leave the shopper's phone and are never saved. Only the derived measurements travel, and only after the shopper reads them on a confirmation screen and taps send. Size Calculation asks the shopper for no account and no password.
Three steps, and only one of them is yours
Size Calculation takes one panel entry and one embed on your side. The shopper does the rest on their own phone.
Open the garment
In the panel, create the garment: product id, gender, the size chart and the fit rule. This is the only place a size decision is configured.
Drop the embed in
One div and one script on the product page. The widget renders the QR for that specific garment and reports the recommended size back to your page.
The shopper measures
They scan the code, tell the app their height once, stand in front of the phone for two minutes, read their own numbers and confirm. You receive the measurements in centimetres and the size for that garment.
The measurements, in centimetres, every time
Size Calculation stores and transmits every value in centimetres. The unit never varies by shopper or locale, so your side never has to guess what a number means. The app shows the shopper both centimetres and inches; only centimetres go on the wire.
| Measurement | Field | Unit | Example |
|---|---|---|---|
| Chest circumference | chest | cm | 96.2 |
| Waist circumference | waist | cm | 81.4 |
| Hip circumference | hip | cm | 99.0 |
| Shoulder width | shoulder | cm | 44.5 |
| Height | height | cm | 178.0 |
| Inseam | inseam | cm | 81.2 |
| Arm length | arm | cm | 61.0 |
Two lines on the product page
The embed is dependency-free and does not care what your storefront is built with. Put the container where the size selector lives, and the script anywhere on the page.
<div data-sizecalc data-garment-id="ball-skirt" data-sizes="XS,S,M,L"></div>
<script src="https://…/embed.js" data-firm="YOUR_FIRM_ID"></script>data-garment-id is the garment you opened in the panel. data-sizes is what you actually have in stock — if the chart's size is not in it, the shopper still sees their real size, with a note that this piece is not stocked in it. data-firm is not a secret and is not expected to be one.
No charge to your shoppers · the widget is yours to style · we answer from a real address
Questions brands ask first
Which phones can measure with Size Calculation?
Any iPhone from the XS and XR (2018) onwards. Pro models from the iPhone 12 Pro use the LiDAR scanner; every other iPhone uses the camera, motion tracking and the shopper's height, which the app asks once. The Android app runs on ARCore-capable phones and is on Google Play.
What happens if the shopper's phone has no LiDAR?
They still measure. The app asks their height once, tracks the floor with the phone's motion sensors and scales the body silhouette from both; the same measurement engine reads the result. Only phones without person detection — iPhones older than 2018 — cannot measure, and your size chart stays as the fallback there.
What does the app ask the shopper?
One thing: their height, once. It is the scale reference on phones without a depth sensor and can be corrected in Settings. Gender, fit, brand and size system are never asked — the garment record you create in the panel answers those.
What data does Size Calculation store?
Camera frames and depth data never leave the shopper's phone and are never saved anywhere. The derived measurements — the centimetre values in the table above — are transmitted and stored so they can be delivered to you, and only after the shopper confirms the transfer.
Does the shopper need an account?
No. Size Calculation asks the shopper for no account, no password and no key. Scanning the QR and confirming on one screen is the entire flow.
How is Size Calculation different from a static size chart?
A static size chart describes the garment and leaves the shopper to work out how it maps to their body. Size Calculation measures the body, then reads the size off the same chart you uploaded — so the shopper never does the translation, and you never hand the decision to a generic table.
Can the shopper see what is sent before it is sent?
Yes, and that screen is not skippable. Size Calculation lists every measurement, in centimetres and inches, on a confirmation screen naming your brand and the garment. Nothing is transmitted until the shopper taps send.
Put the tape measure in their pocket
Open one garment, paste two lines, and the next shopper on that page stops guessing.
Start my integrationThe shopper confirms every transfer · raw scan data never leaves their phone