How browser-based AR foot scanning works
A guided 12-step scan turns a phone camera into a foot-measuring tool. It captures foot length and ball girth to within ±2 mm of a podiatrist scan, then recommends the right size for a specific shoe — all in the browser, with no app to install.
Last updated June 2026 · ARFits Editorial
In short
The shopper opens a scan from the product page. On iOS it launches as an App Clip from the web; on Android it runs through WebXR. A 12-step guided capture takes about 30 seconds and measures foot length and ball girth to within ±2 mm of a podiatrist scan (≈99% accuracy). The system then shows a per-model size recommendation and a fit heatmap, and measurements stay on the device by default.
The 12-step guided scan
The scan is "guided" because the interface walks the shopper through a fixed set of capture positions. Following the guidance is what keeps the result repeatable and accurate — the steps below describe the flow from open to recommendation.
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1
Open from the web
Tap a scan link or QR on the product page. iOS launches an App Clip; Android opens a WebXR session. Nothing is installed from an app store.
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2
Grant camera access
The browser requests the rear camera. Capture and processing run locally on the device.
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3
Set up the environment
Stand on a flat, contrasting floor in good light. Even lighting and a clean background help the system separate the foot from the floor.
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4
Frame the foot
Position the foot inside the on-screen guide. The interface confirms when the foot is correctly in frame before capture begins.
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5–10
Guided multi-angle capture
The shopper moves the phone around the foot through a sequence of prompted positions. Capturing the foot from multiple angles is what allows length and the wider ball-girth dimension to be reconstructed, rather than guessed from a single photo.
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11
Compute measurements
The captured frames are combined into foot length and ball girth, measured to within ±2 mm of a podiatrist scan.
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12
Recommend a size
A recommendation card maps the measurements to the selected model's size, with a fit heatmap and one-tap half-size adjustment.
The whole flow takes about 30 seconds. Steps 5–10 represent the guided capture positions; the exact prompts vary slightly by device.
What the scan measures
Foot length
The heel-to-toe length is the primary input for size. It maps most directly to EU/US/UK sizing on a per-model basis.
Ball girth
The circumference around the widest part of the foot (the ball). Two feet of the same length can need different sizes if one is wider — ball girth is what catches that.
Capturing both length and ball girth is why a guided AR scan can recommend a size with more confidence than a length-only template or a self-reported size chart.
What professional foot measurement captures
A guided AR scan is not inventing a new way to size feet — it reconstructs the same core measurements a shoemaker has always taken by hand. Traditional fitting measures the foot at several defined points, not just its length, because length alone never describes how a foot will sit inside a last. The classic measurement points below are the foundation of bespoke shoemaking and last construction.
Foot length
Measured from the centre of the heel to the tip of the longest toe. This is the primary dimension behind every size system.
Ball (forefoot) girth
The circumference around the joints of the big toe and little toe — the heads of the 1st and 5th metatarsals. This is the key width and fit dimension, and the one an AR scan reconstructs alongside length.
Instep / waist girth
The circumference across the mid-foot, taken over the first cuneiform bone and the bump of the 5th metatarsal. It governs how easily the foot enters the shoe and how it is held at the arch.
Heel girth
The diagonal circumference taken from the instep around the back of the heel. It matters for heel slip and is especially important when fitting boots.
Ankle, calf and under-knee girths (for boots)
Higher up the leg, the ankle, calf and under-knee circumferences are used to construct boot shafts so the upper sits correctly along the whole leg.
Two feet of the same length can still fit a last very differently because they differ in the ratio of instep girth to ball girth — a higher, fuller mid-foot needs a different last from a flatter one even at identical length, which is why length-only sizing so often misses.
From plaster casts to a phone
These dimensions have always been captured with simple craft tools. Historically a shoemaker used a tape measure, a plantograph (an inked box that records a footprint and outline), an outline tool traced around the foot, or a full plaster cast of the foot. The in-store metal Brannock device became the modern standard for length and width. A guided AR scan now reconstructs foot length and ball girth from multiple camera angles — the same measurements the craft has always relied on, taken on the shopper's own phone. (See also how this compares to other fitting methods.)
Measurement points and tooling follow established footwear-trade practice, per Kopyto a obuwie (footwear and last construction).
How ±2 mm accuracy is achieved on a phone
This ±2 mm accuracy from a consumer phone comes from combining several things rather than a single trick:
- •Guided multi-angle capture. Multiple prompted viewpoints give the system enough information to reconstruct 3D foot dimensions instead of estimating from one photo.
- •On-device sensing. The scan uses the phone's camera and motion sensing to establish real-world scale, so a pixel measurement maps back to millimetres.
- •Step-by-step guidance. Because the interface enforces the capture sequence, the inputs are consistent from shopper to shopper — the main reason results are repeatable.
- •Validation against a reference. The ±2 mm figure is stated relative to a podiatrist scan, which is the practical "ground truth" for foot measurement.
Accuracy depends on following the on-screen guidance, adequate lighting, and a suitable surface. Reported accuracy is about 99% versus a podiatrist scan; it is a measurement aid, not a medical device.
How this compares to other foot-scan services
Browser foot-scan accuracy is in line with the rest of the category. Published specs put 3DLOOK's body/foot scan at 96–97% accuracy across 80+ measurements in about 45 seconds, with 95%+ repeatability; Nike's in-store Nike Fit captured 13 data points per foot in under 15 seconds (DesignBoom, 2019). A guided in-browser scan reaches comparable precision without a dedicated app or in-store hardware — the same class of service, delivered on the shopper's own phone.
App Clip (iOS) vs. WebXR (Android)
| Aspect | iOS — App Clip from web | Android — WebXR |
|---|---|---|
| How it launches | An App Clip is invoked from the web — a lightweight, on-demand experience. | Runs directly in the mobile browser via the WebXR API. |
| App-store install | Not required. | Not required. |
| Entry point | Scan link or QR on the product page. | Scan link or QR on the product page. |
| Where data lives | On the device by default. | On the device by default. |
The two paths exist because the platforms expose camera-based AR differently. For the shopper, both feel the same: tap, scan, get a size — no download.
The fit heatmap and recommendation card
Measurements alone do not tell a shopper what to buy. The recommendation step turns them into a decision for a specific model.
Recommendation card
Suggests the best size for the selected shoe, based on the scan plus the model's last and fit profile.
Fit heatmap
Teal shows where the shoe fits comfortably; coral shows where it runs tight. The shopper sees why a size is suggested.
One-tap half-size
Tapping a half-size up or down recomputes the heatmap instantly, so shoppers can weigh a snug vs. roomy preference.
Privacy: measurements stay on the device
By default, the scan's measurements stay on the shopper's device. Because the experience runs in the browser through an App Clip or WebXR — rather than a persistent installed app collecting data in the background — the foot data does not need to leave the phone to produce a size recommendation. This is a meaningful difference from sending photos of your feet to a server.
A secondary benefit: visual AR try-on
The same camera flow can also place the shoe on the foot in augmented reality. This is a secondary feature to the sizing job, but a useful one: it lets shoppers judge look and fit together — does this sneaker suit me, and will this size sit right — before they buy. Sizing remains the core value; the visual try-on is the confidence layer on top.
Frequently asked questions
Do I need to install an app to scan my foot?
No. The scan runs in the mobile browser: on iOS it launches as an App Clip from the web, and on Android it runs through WebXR. No app-store download is required — you tap a scan link or QR on the product page and start.
How accurate is the browser foot scan?
The 12-step guided scan measures foot length and ball girth to within ±2 mm of a podiatrist scan, about 99% accuracy. Accuracy depends on following the on-screen guidance, adequate lighting, and a suitable surface. It is a measurement aid, not a medical device.
What does the scan measure?
It captures foot length (heel-to-toe, the primary input for size) and ball girth (the circumference around the widest part of the foot). Capturing width as well as length is why two feet of the same length but different widths can be recommended different sizes.
What measurements matter for shoe fit besides length?
Beyond foot length, the key dimensions are ball (forefoot) girth — the circumference around the big-toe and little-toe joints — plus instep girth across the mid-foot and heel girth around the back of the heel. Capturing girth, not just length, is what separates a reliable fit from a length-only size chart, because two feet of the same length can carry very different girths.
How long does the scan take?
The whole flow takes about 30 seconds — open from the web, grant camera access, follow the guided multi-angle capture, and receive a per-model size recommendation with a fit heatmap.
Is my foot data sent to a server?
By default, the scan's measurements stay on your device. Because it runs in the browser through an App Clip or WebXR rather than a persistent installed app, the foot data does not need to leave the phone to produce a size recommendation.