Why Mailchimp Subscriber Counts Don't Match WooCommerce Customer Numbers

Many WooCommerce store owners notice discrepancies between their customer count and Mailchimp subscriber numbers after using the 'Mailchimp for WooCommerce' plugin. This common issue can be frustrating, but understanding how the plugin works typically reveals the cause.

Why This Happens

The plugin doesn't sync all WordPress users or WooCommerce customers by default. Its synchronization behavior depends on several factors including order status, customer consent, and your specific plugin configuration.

Common Causes and Solutions

1. Order Status Limitations

The plugin primarily syncs data from orders, not just customer accounts. By default, it only synchronizes 'completed' orders. Customers with orders in other statuses (pending, processing, etc.) may not be synced.

Solution: Check your order statuses and ensure completed orders exist for the customers you expect to see in Mailchimp.

2. Subscription Consent at Checkout

Each order contains a custom field called mailchimp_woocommerce_is_subscribed that records whether the customer opted into marketing during checkout. A value of '0' means they declined marketing permissions.

Solution: Review individual orders to verify the subscription status captured at checkout. This field appears in the order details section under Custom Fields.

3. Plugin Configuration Settings

Your sync settings determine which customers are synchronized. The two main options are:

• Sync all subscribers and customers
• Only sync subscribers (no transactional customers)

Solution: Review your plugin settings to ensure they match your intended synchronization behavior. The 'Mailchimp for WooCommerce' team has updated these options over time, so settings may have changed if you recently updated the plugin.

4. Re-sync Creating Unexpected Subscribers

Performing a full re-sync (especially after uninstalling/reinstalling the plugin) can sometimes add subscribers unexpectedly. This typically happens because the process re-evaluates all historical order data based on current settings.

Solution: Before re-syncing, ensure your settings are configured correctly. Check the subscription status in individual orders if unexpected subscribers appear after a sync.

Checking Subscription Status in Orders

To verify whether a customer consented to marketing:

1. Open the specific WooCommerce order
2. Scroll to the Custom Fields section (usually below order details)
3. Look for the mailchimp_woocommerce_is_subscribed field
4. A value of '1' indicates they opted in; '0' indicates they opted out

When Customers Are Converted to Transactional Status

Some users report subscribers being converted to 'transactional' status, removing them from marketing lists. This typically occurs when customers opt out of marketing during checkout or through other consent mechanisms. Check the subscription status field in their orders to confirm this behavior.

Understanding these synchronization behaviors can help resolve most discrepancies between WooCommerce customer counts and Mailchimp subscriber numbers. The system is designed to respect customer consent preferences captured during the checkout process.