Go to System → Settings → Store Details
The default weight class your store display weights. This setting affect the default weight class when you create new products and the weight class shown in the basket page if Display Weight on Cart Page enabled in your store.
| Warning |
|---|
Do not confuse with base weight class used in calculations. See System → Localization → Weight Classes. Also some shipping methods have own Weight class's related setting which affect shipping weight calculations. |
...