Re: [idempiere] Why does iDempiere forbid converting from larger to smaller UOM for Material?

[Carlos Antonio Ruiz Gomez]

The reason for this validation is that you will have rounding problems when converting from bigger to smaller UOM.

If you are aware of that and can cope with the rounding problems then there is a System Configurator ProductUOMConversionRateValidate for that

Regards,

Carlos Ruiz

https://www.bx-service.com

On 1/14/26 09:56, Usama Ahmed wrote:

Hello everyone,

I am implementing iDempiere for a textile manufacturing client and encountered a question regarding UOM conversions for raw materials. I would appreciate guidance and best practices from the community.

Context

• The client’s raw material is fabric, with Meter as the default UOM.

• Some vendors supply fabric in Yards, which is a smaller quantity than Meter in ERP terms.

• When attempting to set up a product-level UOM conversion from Meter to Yard, the system does not allow converting from a bigger UOM to a smaller UOM.

The default UOM remains Meter due to operational reasons:

• BOM calculations are defined per Meter

• Rates, costing, and other process calculations are also Meter-based

• If Yard were the default, many operational calculations would be impacted

Observations / Questions

1. Is there a logical ERP reason why iDempiere enforces the default UOM to be the smallest unit of measure?

2. Could this constraint cause inventory or costing inconsistencies if we attempt to reverse it or allow conversions from bigger to smaller UOM?

3. Are there standard ERP best practices for handling situations where suppliers provide materials in larger UOMs than the system default?

I am trying to understand whether this is a business control / design limitation or something that can be safely configured, and how other implementations have handled it.

Any insights or experiences would be highly appreciated.

Thank you in advance for your guidance.

Best regards,

Kindly check SS for reference.