Here are 4 cases to demo how many trademarks and classes when trademark registration:   Case 1: One trademark, one class If you are only registering one trademark for one type of product or service, you only need to include one class in your application. For example, if you want to register the trademark "Acme" for use in connection with computer software, you would only need to include Class 9 in your application.   Case 2: One trademark, multiple classes If you are registering one trademark for use in multiple classes, you will need to include each class in your application. For example, if you want to register the trademark "Acme" for use in connection with both computer software (Class 9) and restaurant services (Class 43), you would need to include both Class 9 and Class 43 in your application.   Case 3: Multiple trademarks, one class If you are registering multiple trademarks that all relate to the same type of product or service, you only need to include one class in your application. For example, if you want to register the trademarks "Acme" and "Rocket" for use in connection with computer software, you would only need to include Class 9 in your application.   Case 4: Multiple trademarks, multiple classes If you are registering multiple trademarks for use in different classes, you will need to include each class in your application. For example, if you want to register the trademarks "Acme" and "Rocket" for use in connection with computer software (Class 9) and restaurant services (Class 43), you would need to include both Class 9 and Class 43 in your application.