How Mizzen+Main Built a Smarter Fit Experience

When a leading apparel brand pairs world-class fabrics with fit intelligence, the results speak for themselves. For Mizzen+Main, that journey started with the Smart Size Chart™ and evolved into one of the most engaging fit experiences in men's retail, a four-stage system that's driving higher conversion, stronger order values, and fewer returns across its entire product line.

Here's how they did it.

The Brand Behind the Button-Down

Mizzen+Main built its reputation on a simple premise: dress shirts that perform like athletic wear. Made with moisture-wicking, stretch fabrics, the brand disrupted the traditional button-down category by making comfort and professionalism inseparable. But as its product catalog expanded, a familiar challenge emerged: how do you help online shoppers confidently navigate multiple styles, fits, and sizes without a fitting room?
Good fabric wasn't enough. The brand needed smart technology.

Step 1: Building the Foundation with the Smart Size Chart™

Mizzen+Main's fit journey with Bold Metrics began with the Smart Size Chart™, a Solution that replaced its static sizing grid with something far more intelligent.

Traditional size charts are built on assumptions: that a given size represents consistent proportions across all body types, and that shoppers already know their measurements. The Smart Size Chart™ works differently. Shoppers enter just four to six simple inputs, and Bold Metrics' AI instantly generates 50+ body measurements, creating a detailed digital twin of each shopper. That digital twin is then mapped against Mizzen+Main's actual garment construction data to evaluate how a specific shirt or pant will fit at key points such as the chest, waist, hip, and sleeve length.

The results were immediate:

• 20% conversion rate among Smart Size Chart™ users
• 19% higher average order value for users vs. non-users
• 78% completion rate among shoppers who clicked "Find My Size"

These aren't just metrics. They reflect what happens when shoppers buy with confidence and what's possible when a size recommendation is built on real body data and real garment specs, not industry averages.

"Bold Metrics has been a key driver in improving our ecommerce performance. By helping customers make more confident sizing decisions, we've significantly reduced return rates and seen a clear lift in both AOV and conversion rate." — Natalie Shaddick, VP of eCommerce, Mizzen+Main

Step 2: The Shirt Finder — From Sizing to Personalization

With the Smart Size Chart™ proving the value of AI-driven fit guidance, Mizzen+Main and Bold Metrics took the next step: a fully personalized shopping experience called the Shirt Finder.

Rather than telling shoppers their size, the Shirt Finder helps them find the right shirt entirely. A short, intuitive quiz asks about body, lifestyle, and style preferences, then narrows the full dress shirt assortment to a curated set of personalized recommendations, each with the right size. The experience was designed for Mizzen+Main's core shoppers: busy, goal-oriented men who want to find what they're looking for quickly.

The root problem the Shirt Finder was designed to solve? Decision fatigue.

"When a customer has to navigate too many options regarding fit, print, and pattern without personalized guidance, that hesitation often leads to cart abandonment. Our core demographic of men typically prefer a highly streamlined shopping experience; they generally aren't looking to browse for long periods of time." — Natalie Shaddick, SVP of Marketing, Mizzen+Main

From its July launch through early October alone, more than 5,200 shoppers used the Shirt Finder. In September, the Solution achieved a 32% engagement rate. Most significantly, the Shirt Finder contributed to a 7% increase in total revenue within months of launch, and conversion rates for customers who took the quiz more than doubled.

Step 3: The Pant Finder — Expanding Category by Category

The Shirt Finder's success made one thing clear: this model had legs... literally.

Pants present a unique sizing challenge. Unlike shirts, where the primary fit concern is the torso, pants must account for waist, inseam, hip, rise, and thigh measurements simultaneously, and the interplay between these dimensions varies significantly from person to person.

The Pant Finder offers shoppers a guided two-minute quiz. A few simple inputs, height, age, typical waist size, and weight generate a digital twin, which is then mapped to Mizzen+Main's specific garment data to deliver fit guidance that goes far beyond what a generic size chart could ever provide.

"It was critical for us to prioritize that category to truly understand the data and perfect the customer journey first. However, as we continue to build out our assortment of bottoms and expand into new fits and fabrics, applying this same technology to pants is next on our list." — Natalie Shaddick

Step 4: Busting Bracketing: How Mizzen+Main Cuts Down on Duplicate Size Orders

Bracketing is one of the most common and costly behaviors in online apparel. It happens when a shopper is unsure of their size, so they order the same item in two or more sizes, keep the one that fits, and send the rest back. For the shopper, it feels like a reasonable workaround. For the brand, it means inflated return volumes, higher fulfillment costs, and inventory that cycles in and out without ever generating a clean sale. And because it tends to happen quietly across thousands of orders, it can be easy to miss until the return rate data tells a different story.

Mizzen+Main addresses this directly in their shopping cart. When a shopper adds more than one size of the same product to their cart, the site surfaces a prompt flagging the potential duplicate and directing them to a Find My Size quiz. Instead of completing a bracketing order, the shopper gets a fit recommendation and checks out with their best fit.

The Find My Size quiz is powered by Bold Metric’s Virtual Sizer and built on the body data Mizzen+Main has accumulated across its shopper base. That foundation is what makes it more than a standard sizing solution; it draws on the same fit intelligence behind the Smart Size Chart, Shirt Finder, and Pant Finder to deliver a recommendation shoppers can trust.

The Technology Underneath

What powers each step of this journey is Bold Metrics' AI body data platform. Shoppers provide a small number of inputs; Bold Metrics' algorithms translate those into a comprehensive digital twin in milliseconds. That twin is then mapped against Mizzen+Main's actual garment specs, not generic industry averages.

The platform also captures individual fit preferences. Two shoppers with identical measurements may prefer entirely different silhouettes: one wanting a trim, athletic cut, the other preferring a relaxed, everyday fit. Bold Metrics factors this preference layer into every recommendation, ensuring guidance reflects both how a garment fits a body and how the shopper wants it to feel.

Beyond the customer-facing experience, the aggregated body data tells Mizzen+Main something equally valuable: which body segments are underserved by current size offerings, and where a new fit block might unlock a new customer segment.

"Aggregated body data can reveal underserved body segments within a brand's customer base. These insights inform broader product development decisions, including where fit coverage can expand and how silhouettes may evolve." — Daina Burnes, Founder & CEO, Bold Metrics

A Blueprint for Personalized Fit at Scale

The numbers across each phase of Mizzen+Main's journey tell a consistent story: when customers are empowered with personalized fit guidance, they buy more confidently, spend more, and return less.

What Mizzen+Main and Bold Metrics have built together is more than a fit Solution. It's a personalized commerce experience that starts with a body and ends with a confident, satisfied customer. For other DTC brands watching this story unfold, the takeaway is clear: personalization at the fit level isn't a luxury feature. It's a growth strategy.