How accurate is the AI size prediction?
Our AI achieves around 92% accuracy for top size predictions and 88% for bottoms. Accuracy improves when you provide body shape and preferred fit details alongside measurements.
✦ AI-powered sizing
Never order the wrong size again
SizeWise uses AI to predict your perfect clothing size across 500+ brands — based on your body, preferred fit, and real customer reviews.
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Trusted by 50,000+ shoppers worldwide
Brands covered
Nike
Zara
H&M
Adidas
Levi's
Uniqlo
ASOS
Mango
GAP
Topshop
& 490+ more
What we do
Everything you need to shop with confidence
From simple size conversions to deep AI fit predictions — we've got every angle covered.
Size Converter
Instantly convert between US, UK, EU, JP, IT, FR, AU sizing systems for clothing, shoes, and bras. Handles numeric and letter sizes alike.
AI Fit Predictor
Enter your height, weight, body shape and fit preference. Our AI predicts your exact size in tops, jeans, dresses, and shoes across brands.
Brand Comparison
Ask "Does Zara run small?" and get AI-powered analysis based on customer reviews, sizing patterns, and brand-specific fit data.
Body Measurement Guide
Not sure of your measurements? Our guide shows exactly how to measure chest, waist, hips and inseam for accurate results.
International Coverage
Supporting shoppers across the UK, US, EU, Asia, and Australia. All size standards from every major fashion market.
Returns Reducer
Get it right the first time. Our predictions are built to slash return rates — saving you time, hassle, and the environment.
How it works
Your perfect size in 30 seconds
No measuring tape needed. Just a few questions and our AI does the rest.
1
Tell us about you
Enter your height, weight, age and preferred fit style — slim, true to size, or oversized.
2
Choose your brand
Pick from 500+ supported brands, or ask a general question about any clothing category.
3
AI analyses data
Our model combines your measurements with brand-specific fit data and real customer reviews.
4
Get your size
Receive a clear, confident size recommendation with a full explanation — and a confidence score.
Try it now — it's free
Find your size right now
No account needed. Powered by Claude AI.
Fill in your details and we'll predict your perfect size.
✦ AI recommendation
Enter a size above to see international equivalents.
⇄ Size conversion
Ask about any brand's sizing to get AI-powered insights.
🏪 Brand insight
Common questions
Frequently asked questions
Which size systems do you support?
We support US, UK, EU, Japan (JP), Italy (IT), France (FR), and Australia (AU) for clothing and shoes across all genders and age groups.
How does brand sizing comparison work?
Our AI analyses sizing patterns, customer review data, and brand-specific cut information to summarise whether a brand runs small, true to size, or large — and by how much.
Is SizeWise free to use?
Yes, the core tools — size converter, AI fit predictor, and brand guide — are completely free to use with no account required.
What if I'm between sizes?
The AI accounts for in-between measurements and will recommend the best option based on your stated fit preference (slim, true to size, relaxed, or oversized).
Can I use SizeWise for children's sizing?
Yes! The size converter supports children's clothing and shoe sizes across all major international systems. The AI fit predictor for kids is coming soon.
Stop guessing. Start wearing.
Join 50,000+ shoppers who get it right the first time.
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