The sizing platforms fashion brands use: ten compared, and where Garu fits.

Every fashion brand of any size has been pitched a sizing tool, and the pitches sound alike: fewer returns, higher conversion, a widget on the product page. Underneath, the ten platforms below are different products. This guide sorts them by the one thing that matters most, what the shopper has to give and what they get back, with each vendor's own facts as published on September 21, 2026. Garu is on the list and made this page, so read the last row accordingly.

The one question that sorts them

Where does the size come from? There are three answers, and they behave differently as bodies change and as the buy button moves off the product page.

• Purchase history. What this shopper, or shoppers like them, bought and kept. Needs no effort from the shopper; assumes bodies are stable. True Fit is the reference example.
• A few questions. Height, weight, age, sometimes body shape and fit preference, mapped to a model. Cheap and quick; a proxy for the body rather than a measurement of it. Bold Metrics, Prime AI, Sizebay.
• The body now. Measurements taken at the moment of decision, from a photo or entered by the shopper, matched to the garment's own chart. Garu, CATCHES, 3DLOOK.

The ten

Notes on each

True Fit is the incumbent, with Walmart, Target and Lululemon on its wall and a claimed 72% share of the category. Its strength is a network of outcomes no one else has. Its weakness is the same thing: a recommendation from history assumes the body has not moved, and it is moving.

Fit Analytics has the longest European track record, was bought by Snap for about $124 million in 2021 and bought itself back after Snap closed its enterprise AR unit. Enterprise-only, no published price.

Bold Metrics builds a digital twin from questions rather than photos and launched an Agentic Sizing Protocol with Gap on 24 March 2026, the first public sizing standard for AI shopping agents. Worth watching for anyone planning agentic checkout.

Virtusize is the Asia-Pacific leader, Tokyo-based, 500-plus brands. Its Shopify app page said "not currently available" on the check date, so confirm before planning around it.

Sizebay and Prime AI are the free, question-based Shopify options. Both are young on the App Store; Prime AI sells try-on as credits, Sizebay describes photo try-on on its site.

Naiz Fit has strong Spanish and Italian references and product-team audits. Its parent MySize announced a defense-technology strategy on 14 September 2026, which merchants should read before signing.

Kiwi Sizing is the best size-chart app on Shopify and, for a store with messy charts, the first money to spend. It is a chart, not a fit engine.

CATCHES is the new luxury entrant: physics-simulated cloth on NVIDIA hardware, launched with AMIRI in March 2026, $10 million raised, bespoke integration only.

3DLOOK measures from two photos in 45 seconds. Its site now leads with FitXpress, a body-data and BMI product, and Mobile Tailor for made-to-measure, rather than retail sizing.

Where Garu fits

Garu is the Shopify app in the third group. One photo gives the shopper's chest, waist and inseam; those are matched to your chart for the garment on the page; the shopper gets a size, a fit note and a render of themselves wearing it, front and back. On Garu Plus each size is rendered as its own garment. It publishes its price, installs as a theme embed, and has one App Store review. It has no outcome network and no enterprise logos, and the pages linked in the table say so for each vendor. What it has is the answer built from the body in front of it, and the picture to go with it.