A simple two or three question survey is all that is required to provide users with the exact size that fits them best.


Fit Predictor uses customers’ past purchase history to develop a unique Fit Profile that is refined as users shop.

100% of customers

Fit Predictor provides personalized sizing recommendations to all shoppers, even those without Fit Profiles.

Switch to Fit Predictor on Desktop
Fit Predictor your best size: M
Switch to Fit Predictor on Mobile
Fit Predictor your best size: M


Click on Fit Predictor to start

Your Fit Profile

The “Your Fit Profile” screen provides customers with insight into how a prediction is made via a list of their past purchases in a clear and editable format. By giving users the option to mark an item as a gift, remove a garment from the profile or add an additional item, shoppers can customize their profile to fit them best.

Click on the Calculator tab Add more button to see more.

Calculate Your Size

When a new customer opens Fit Predictor they are greeted by the “Calculate Your Size” screen. This simple survey allows the user to select a garment they love the fit of from a carefully crafted set of brands. Once the survey is complete, Fit Predictor calculates their best fitting size in seconds.

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How does it work?

Fit Predictor finds a customer's best fit in seconds using existing data, without the need for physical measurements. For new customers without a shopping history, the service can predict the best fit based on the customer's sizing with other brands. Fit Predictor is currently being used by over 100 million active users per month.

Fit Predictor is globally available and supports more than 60,000 brands. The technology has been proven to increase conversion and reduce returns.

"Using existing data from retailers, we've created a service that helps customers find the right fit, reduces barriers to online shopping and decreases returns. It works in seconds without the need for customers to enter any data," said Zoli Piroska, founder and CEO, Secret Sauce Partners. "Fit Predictor's new data-driven approach to fit, including a private, non-invasive user experience that doesn't use any measurements from people or products, sets it apart and is the reason it has been adopted by tens of millions of consumers. In the end, it's a service that benefits customers as much as it benefits retailers."

In numbers

100 million

active users a month

70 million

people with fit profiles


size recommendations per second on average


supported brands