Dynamic Business Central 365: How to Default Purchase Unit of Measure Based on Vendor in Business Central (No Customization)

Problem Statement

In Microsoft Dynamics 365 Business Central, it is common to source the same item from multiple vendors.
However, challenges arise when:

• The same item is purchased from two different vendors

• Both vendors use the same vendor item number

• Each vendor sells the item in a different Purchase Unit of Measure (UoM)

  • Vendor A sells in packs

  • Vendor B sells individually

The requirement is to automatically default the correct Purchase Unit of Measure on the Purchase Order line based on the selected vendor—without manual intervention.

Standard Business Central Solution (No Customization Required)

The correct and supported solution is to use Item References.

Key Concept: Item Reference

Item References allow you to define vendor-specific purchasing details for the same item, including:

• Vendor No.

• Vendor Item No.

• Purchase Unit of Measure

• Pricing (via Purchase Price Lists)

How to Configure the Solution

Navigate to Item Reference List. 

For the same inventory item, create multiple Item Reference lines: The Item Reference No. can be the same, because the Vendor No. differentiates the records.

Use Item Reference on Purchase Orders

On the Purchase Order Line:

Select the Item Reference instead of manually selecting the Item No.

Business Central will automatically:

• Populate the Item No

• Set the correct Purchase Unit of Measure

• Apply the correct pricing from Purchase Price Lists

[SS Vendor 2]

Result

• Purchase UoM defaults correctly based on vendor

• No manual changes required

• Pricing logic works automatically

• Fully supported, upgrade-safe solution

• No AL customization needed

Conclusion

If the same item is purchased from multiple vendors with different purchase units, Item References are the correct and recommended solution in Business Central.
They allow vendor-specific behavior while keeping inventory management centralized and clean.

Thanks For Reading..!!😊😊

Regards,

Khushbu Rajvi