How Size Agent Works on WooCommerce: A Complete Guide

WooCommerce powers millions of online stores — and if you're selling apparel on WordPress, you already know that sizing is one of your biggest challenges. Customers can't try things on, size charts are confusing, and returns eat into your margins.

Size Agent solves this by adding an AI-powered sizing chatbot directly to your WooCommerce product pages.

How It Works

Size Agent is a lightweight JavaScript widget that sits on your product pages. When a customer clicks "Find My Size," it opens a friendly chat interface that asks a few simple questions and recommends the right size for that specific product.

Behind the scenes, Size Agent reads the size chart image on your product page and uses AI to match the customer's measurements to the right size. It handles bilingual sizing, petite and tall variants, and even warns customers when a product length might not suit their height.

What You Need

Before installing, make sure you have:

• A WooCommerce store on WordPress
• Size chart images uploaded to your product descriptions (with "siz" in the filename)
• A Size Agent account (30-day free trial, no credit card)

Installation: Two Options

Option 1: functions.php (Quickest)

This method adds the Size Agent widget to all your WooCommerce product pages in about 2 minutes.

1. In your WordPress admin, go to Appearance → Theme Editor
2. Select functions.php on the right
3. Add the following code at the bottom:

function add_size_agent_widget() {
    if ( is_product() ) {
        echo '<script src="https://your-size-agent-url.vercel.app/widget.js" defer></script>';
    }
}
add_action( 'wp_footer', 'add_size_agent_widget' );

4. Replace your-size-agent-url.vercel.app with your actual Size Agent URL
5. Click Update File

Option 2: mu-plugins (More Robust)

This method is better for stores that change themes frequently, since mu-plugins run regardless of which theme is active.

1. Connect to your server via FTP or your hosting file manager
2. Navigate to wp-content/mu-plugins/ (create the folder if it doesn't exist)
3. Create a new file called size-agent.php
4. Paste the same PHP code from Option 1
5. Save the file — it activates automatically, no need to enable it

Setting Up Your Size Charts

Size Agent reads size chart images automatically. For it to work on a product:

1. In your WooCommerce product editor, scroll to the Product description
2. Insert your size chart image
3. Make sure the image filename contains "siz" (e.g., size-chart.jpg or scrub-sizechart.png)

Size Agent will find and read the image automatically. No manual data entry required.

What Customers See

When a customer lands on your product page, they'll see a "Find My Size" button near the Add to Cart button. Clicking it opens a chat window that:

1. Asks for their height and weight
2. Optionally asks for specific measurements (chest, waist, hips)
3. Asks about their fit preference (relaxed, fitted, etc.)
4. Recommends their size with a brief explanation
5. Warns them if the product length (petite, tall, regular) might not suit their height

The whole interaction takes under a minute and gives customers the confidence to buy.

Tracking Performance

Every size recommendation is logged to your Size Agent analytics dashboard. You can see:

• Total recommendations given
• Which products are used most
• Top recommended sizes
• Recent activity

This data is invaluable for understanding your customers and optimizing your inventory.

Getting Started

Size Agent works out of the box with WooCommerce. The 30-day free trial gives you enough time to see a real impact on your return rate and conversion rate before deciding whether to continue.

Book a free strategy call →