Clothing Size Finder helps retailers to reduce refunds by guiding shoppers to the right size with high accuracy.
Choose the Lite version for fast deployment via Shopify App Store, or get best results with PRO version which is 100% customisable and is powered by predictive AI. Pro learns exclusively from your actual inventory, product composition, customer reviews, sales and refunds data, and other data points, delivering unmatched accuracy and deeper personalisation for your customers by integrating into your ERP, CRM etc. Are you seeking quick uplift or long term competitive advantage? Prime AI offers solutions tailored to your business goals and budget.
Reduce Refunds with Clothing Size & Fit Finder

Less Returns*
*Shoppers ordering recommended size versus shoppers ordering without size recommendation.
How Size finder Works
Depending on your business needs, shoppers can either:
- Answer a few questions such as: height, weight, body shape (100% customisable in the Pro)
- Or receive instant size recommendations with no input at all, based on their previous purchases, refunds and other available data.
Provide completely frictionless experience with Prime AI. We can generate sizing recommendations by utilising your existing customer data across different systems without asking your shoppers to fill out anything. Ready to provide even more elegant shopping journey?





Results & Case Studies
- More than 50% of your sales will get size advice (PRO version)
- 31% lower returns
- +3% - 15% increase in CVR
- Higher customer loyalty
- Improved profitability
Prime AI’s predictive technology adapts uniquely to each retailer’s catalogue, customers, inventory delivering significant impact across core e-commerce KPIs.
Two levels of service
Lite
- Go live in minutes via the Shopify App Store
- Single size model applied across your full catalogue
- Immediate impact on returns and conversion
- Ideal for fast deployments and smaller inventories
Pro
- Custom-built neural size models at product and colour ID level
- Learns fast from sales, returns, customer reviews, and other data
- Supports predictive sizing without requiring shopper inputs
- Designed for complex catalogues, premium brands, and strategic growth
- Dedicated account manager
What Prime AI Brings to Your Business
- Reduces bracketing, size related refunds and boost profitability
- Offer frictionless shopping experiences even without asking questions
- 100% Customisable at front end and back end to match your business needs
- Seamlessly integrate into any e-commerce, app, and the rest of tech stack (loyalty, CRM, marketing)
- Identify missed sales opportunities to stock outs and product assortment limitations
- Supports all product types: swimwear, lingerie, outerwear, formalwear, menswear, womenswear, kidswear without any limitations.
- No restrictions on the number of brands, categories, or SKUs.
Inside Prime AI Technology
Advanced AI that learns from your actual inventory, your actual customers and makes an actual difference to the KPIs. Prime AI’s Clothing Size & Fit Finder is built with the latest advances in AI predictive modelling, LLMs delivering smarter, more accurate size recommendations than ever before.
Predictive AI Models
Prime AI forecasts the right size for every shopper by analysing real purchase data, returns, customer behaviour patterns, and product relationships, not just static size charts. We deliver sizing recommendations down to Product ID and even Colour ID level for maximum accuracy, unlike other size recommendation tools.
Collaborative Filtering (Smart Size Matching)
Using similar logic to platforms like TikTok, Prime AI groups shoppers with similar profiles and products with similar fits. This allows the system to predict sizing even for first-time buyers or newly launched collections.
Large Language Models (LLMs) for Review Analysis
We automatically extract meaningful sizing insights from customer reviews such as: notes about tight sleeves, waist fit, or fabric stretch to improve recommendations without needing manual tagging to enrich data collected from the customer service department and the refunds process.
Dynamic Fit Messaging
Prime AI doesn’t stop at recommending a size. We dynamically guide shoppers if data suggests they should size up, size down, or stick with their recommended size, reducing sizing errors before checkout.
Frictionless Sizing Without Customer Input
For brands who want a seamless luxury experience, Prime AI can predict sizes automatically based solely on previous customer purchases and other data without requiring any questions to be answered.
Don't leave money on the table
- Identify missed sales opportunities due to stock outs.
- Improve inventory planning by knowing exactly which sizes to stock more (and less)
- Reduce dead stock in your warehouse and avoid losing profitability.
- Understand true customer demand for every size, at product and category level.
- Improve product assortment by seeing who converts best for each product.

Dashboard
- You get full transparency with Prime AI.
- See how many customers actually order the size we recommended and what their return rate is. (Many tools hide this because often customers don’t order the recommended size, and even when they do, return rates stay high.)
- Monitor refund rate reductions linked directly to Prime AI sizing advice
- Identify products where customer expectations vs reality cause sizing mistakes
- Track conversion uplift among shoppers who interacted with Prime AI
- View true size demand trends across products, brands, categories, and regions
- Spot missed sales opportunities when high-demand sizes are out of stock
- Access actionable insights to optimise your stock planning, sizing strategy, and future product development

Alternative Produktempfehlungen
If a customer’s preferred size is out of stock, Prime AI doesn’t show a dead-end. Instead, we recommend alternative products that are in stock, in the shopper’s correct size, and most visually or categorically similar to what they originally wanted. Recommend only products available in the customer’s correct size
- Enhance discovery with Prime AI’s Visual and Vector Search surface products that are visually closest in style, shape, and design attributes
- Fully customisable recommendation logic to fit your merchandising strategy (e.g., brand-first, price-first, colour-first)
- 40% shoppers stay engaged, find alternatives faster, and continue buying without frustration when they get an alternative recommendation from Prime AI.

Back in Stock Alerts
- Send personalised back-in-stock alerts when the customer’s correct size becomes available again
- Fully managed by Prime AI, fast and easy setup.
- Or integrate with your internal CRM, CDP, or marketing platforms. Prime AI can push size availability data to trigger your own custom alerts.
- Increase re-engagement rates and recover sales that would otherwise be lost
Integration
Lite
- Live in minutes through the Shopify App Store
- Ideal for fast deployment without heavy technical work
- No heavy manual data entry required from your team
- No need for complete or perfect size charts from suppliers
- Designed for Shopify-based retailers looking for immediate sizing impact
Pro
- Average deployment time: ~3 weeks (depends on customisation level)
- Works on any platform: Shopify Plus, WooCommerce, Square Space, Salesforce Commerce Cloud, Adobe Commerce (Magento), SAP Commerce Cloud, custom-built websites, mobile apps
- Full API access for deep integrations with CRM, ERP, Loyalty Systems, VTO providers, or any third-party systems
- No heavy manual data entry required from your team
- No need for complete or perfect size charts from suppliers
- We adapt our system to the data that you have, and what to share whether it’s complete, partial, or inconsistent.
- We don’t prescribe rigid formats so you stay in control of your operations.
- Supported by Prime AI’s technical team and your Dedicated Account Manager
Power for Your Ecosystem
Extend sizing intelligence beyond your website, Prime AI’s APIs integrate seamlessly into your wider retail ecosystem.
Virtual Try-On (VTO) Integrations
Prime AI’s APIs provide detailed human body dimensions, enabling VTO providers to create more accurate, personalised avatars for better online try-on experiences.
Custom Clothing and Made-to-Measure Solutions
For businesses offering tailor-made clothing, Prime AI predicts precise body measurements without requiring manual tape measurements supporting truly personalised garment creation.
Flexible API Architecture
Prime AI’s APIs are built to connect with your CRM, ERP, Loyalty Programs, VTO systems, and Marketing Platforms allowing full personalisation of shopper experiences across channels.