| Siebel Forecasting Guide > Forecasting (End User) >  Setting a Default Unit of Measurement
 All participants must define a default unit of measurement (UoM) in each category of UoM that they use in their forecasts. To set a default unit of measurement 
From the application-level menu, choose Tools, then User Preferences.
On the link bar, click Unit of Measurement.
Either create a new record and select the required category and unit of measurement, or change the unit of measurement in an existing record. 
The fields are described in the following table: 
    |  |  |  
    | Category | The category of unit of measurement. Select Length, Volume, or Weight. |  
    | Unit of Measurement | The preferred unit of measurement for the user (manager or sales representative) |  |