Never buy the wrong size again.
Enter your measurements once, and Butter highlights the best size for you on every product page — so you never have to guess again.
Works with your favorite stores
Whether you're browsing denim, picking up a dress shirt, or shopping activewear — Butter finds your size across thousands of retailers.
How It Works
Three steps. Perfect fit.
01
Set Up Once
Enter your height, weight, chest, waist, and fit preference. Your profile is saved securely in your browser.
02
Shop Normally
Visit any clothing product page and Butter appears near the size options with a simple "Show Me My Size" button.
03
Purchase with Confidence
Butter compares your measurements to the brand's size chart and highlights your recommended size instantly.
Why Butter
Online sizing, smoothed out.
No more size charts
Stop squinting at confusing size guides. Butter reads them so you don't have to.
Brand-to-brand consistency
A Medium at Nike isn't a Medium at Zara. Butter accounts for brand-specific sizing.
Fewer returns
Order the right size the first time and skip the hassle of returns and exchanges.
Your data stays private
Your measurements are saved locally in your browser. Butter never sends them to a server.
Stop guessing. Start fitting.
Join thousands of shoppers who never get the wrong size. Install Butter today — it's free and takes seconds.