How to Set NMFC Numbers with Shopify Metafields

Shipduo adds NMFC and NMFC Sub metafields to your Shopify products automatically when you install the app. Add the product's NMFC number and NMFC sub to automatically apply the correct freight classification details during checkout and shipment booking.
When these fields are populated, Shipduo uses them to prefill the NMFC information on rate requests, shipment details, and BOLs — helping improve rating accuracy and reduce manual entry.

📋 Good to know: These metafields are created for you on install. You just enter the values on the products you want to control.

What These Metafields Do

• NMFC — the National Motor Freight Classification item number for the product.
• NMFC Sub — the sub-number that goes with it.

When both are populated on a variant, Shipduo applies the correct freight classification automatically — prefilling the NMFC details on rate requests at checkout and on shipment details and BOLs at booking. If you leave them blank, Shipduo determines the freight class on its own (based on dimensions and weight).

Where to Find Them

1. In your Shopify Admin, go to Products and open a product.
2. Scroll to the Variant metafields section (or open an individual variant).
3. Locate the NMFC and NMFC Sub fields.

How to Set Them

1. Open the product (and the specific variant) in your Shopify Admin.
2. Enter the product's number in the NMFC field.
3. Enter the matching value in the NMFC Sub field.
4. Click Save.

That's it — Shipduo will now prefill these numbers wherever the product is rated and booked.

Why Use This

• Improved rating accuracy: the correct freight classification is applied consistently at checkout and booking.
• Less manual entry: the NMFC details are prefilled on rate requests, shipment details, and BOLs, so there's nothing to re-type.
• Consistency end to end: the same classification flows from the customer's checkout quote through to the BOL.

💡 Tip: Use this for products with a known, fixed NMFC classification. For items where you'd rather let Shipduo determine the class from dimensions and weight, simply leave these fields blank. For related setup, see How to Set Up Shipduo Routing Metafields in Shopify.

Troubleshooting

• Don't see the NMFC fields? They're added automatically when the Shipduo app is installed. If they're missing, confirm the app is installed, or add the metafield definitions manually (see How to Add Dimensions to a Shopify Metafield for how to use Add definition).
• Your NMFC isn't being prefilled? Make sure both NMFC and NMFC Sub are filled in correctly on the variant.
• Need help? Chat with us or contact Shipduo Support.

Updated on: 29/06/2026