Automatic update of item UoM quantities

Standard Measurements  •  Article  •  6/4/2025  • 

The automatic update of item UoM quantities feature ensures that when adding or updating units of measure (UoM) for an item, the Quantity Expressed in the UoM field or Quantity Expressed in Base UOM field value is automatically calculated, especially when units of measure belong to the same UoM group code. This automatic calculation helps maintain consistency and accuracy when converting between different units of measure for the same item.

If a unit of measure is configured with a UoM group code, the Quantity Expressed in the UoM or Quantity Expressed in Base UOM field value will be automatically populated based on the conversion ratios defined on the Unit of Measure and Unit of Measure Groups pages. The system uses the option selected in the Method of Expressing Relation to Base UOM field on the Unit of Measure Groups page to determine which field to update. For more information, see Unit of measure and Unit of measure groups.

First inserted record for UoM group code

If the selected unit of measure is configured with a UoM group code and it is the only line with that UoM group code in the item units of measure, the value in this field is automatically set to 1. You must employ the standard procedure of manually updating the values related to the base unit of measure. The updated value will be used in subsequent calculations for any new record for the same UoM group.

Subsequent inserted records for UoM group code

If the item units of measure already includes a record with the same UoM group as the newly inserted record, the system automatically calculates the ratio between the two units of measure.

The system follows this process:

  • If the baseline unit of measure of the UoM group already exists on the Item Units of Measure page, the system uses it to calculate the ratio.
  • If the baseline unit of measure is unavailable, the system compares the new UoM with the first available record on the Item Units of Measure page that has the same UoM group code.
    > [!NOTE]
    > If the baseline unit of measure of the same UoM group is added later, the system automatically recalculates and updates the ratio for all relevant units of measure within the same UoM group.

The ratio is calculated using the values in the Quantity Expressed in the UoM or Quantity Expressed in Base UOM fields from the Units of Measure page, and the result is used to set the appropriate value for the newly inserted UoM record.

Here’s an example of scenarios:

UoM group code configuration

Let’s assume that OZ, KG, and LB belong to the same UoM group code, Weight, with KG being the baseline unit of measure for the relevant UoM group code. The item has a base unit of measure BOX, which is not configured with the Weight UoM group code.

On the Units of Measure page, the values for the Qty. per Baseline UOM and Baseline UOM Quantity fields are set as per the universal conversion ratios among these weight units:

Qty. per Baseline UOM

KG = 1
LB = 2.20462262
OZ = 35.273962

Baseline UOM Quantity

KG = 1
LB = 0.45359237
OZ = 0.0283495231

Scenario 1: Adding the first unit of measure (KG)

When KG is added to the item units of measure since there are no existing lines with the same UoM group code, the system calculates the Quantity Expressed in the UoM and Qty. per Unit of Measure field values using the net weight value of the item and the ratio between the newly added UoM (KG) and the base unit of measure of the item (BOX).

The system uses the configuration defined in the Method of Expressing Relation to Base UOM field on the Unit of Measure Groups page for the associated UoM group to determine this ratio. For more information on the calculation, see Scenario 2.

However, you must manually update the values to accurately reflect the conversion ratio between the unit of measure and the baseline unit of measure.

For example, if 0.5 KG equals 1 BOX, the Quantity Expressed in the UoM field value for KG should be updated to 0.5.


The KG record may also be automatically inserted when you edit the value in the Net Weight field on the Item Card page, if KG is selected in the Standard Weight Unit of Measure field, and the Update Item UOM with Item Change toggle on the Standard Measurements Setup page is turned on.

Scenario 2: Adding LB

When LB is added to the item units of measure, and there is already another record for the Weight UoM group code, the system compares the two values across units of measure.

The system compares the values based on the configuration of the Method of Expressing Relation to Base UOM field on the Unit of Measure Groups page for the relevant UoM group as follows:

Method of Expressing Relation to Base UOM = Always Qty. per Base UOM

The Qty. per Baseline UOM field values are used to establish the conversion ratio, where there is 2.20462 LB per KG. Since there are 0.5 KG per BOX for this item, the system calculates that there is 1.10231 LB per BOX (calculated as 2.20462 * 0.5). This value is updated in the Quantity Expressed in the UOM field on the Item Units of Measure page.

Method of Expressing Relation to Base UOM = Always Base Qty. per UOM

The Baseline UOM Quantity field values are used to establish the conversion ratio, where there is 0.45359237 KG per LB. Since there are 0.5 KG per BOX for this item, the system calculates that there is 0.90718 BOX per LB [calculated as 1 / (2.20462 * 0.5)]. This value is updated in the Quantity Expressed in Base UOM field on the Item Units of Measure page.

Method of Expressing Relation to Base UOM = Larger Uses Base Qty. Per UOM

The system first applies the Always Qty. per Base UOM option. If the resulting ratio is less than 1, it switches to using the Always Base Qty. per UOM option instead, to avoid small decimal values.


After the automatic calculation, you have the option to manually edit the values for this record if needed.

Scenario 3: Adding OZ without KG (baseline unit of measure)

If the Item Units of Measure page does not include a record for KG, which is the baseline unit of measure for the Weight UoM group, and OZ is added, the system checks for existing records with the same UoM group. If LB is the first available record, the system uses the units of measure table to calculate the ratio between LB and OZ, as described in Scenario 2.


If the baseline unit of measure of the same UoM group is added later, and the Net Weight field value is modified on the Item Card page, the system automatically recalculates and updates the ratio for all relevant units of measure within the same UoM group.

After this calculation, if you modify the Net Weight field value on the Item Card page, the system recalculates and updates all related values based on the updated net weight.


After the automatic calculation, you have the option to manually edit the values for this record if needed.

This calculation occurs only when the unit of measure is configured with the UoM group code. Also, this value in the item units of measure lines will not be updated even if the item’s base unit of measure is modified after this calculation. However, you can manually update it if needed.