Some dog breeds are easy to tell apart. No one should confuse, for example, a Chihuahua and a Tibetan Mastiff. On the other hand, there are some dog breeds which have subtle differences. This is the case with the English Golden Retriever as compared to the American Golden Retriever. Still, if you know what you are looking for, you should easily be able to tell between the two types of dogs.
The term "golden" does not simply refer to a dog with a yellow coat. In the case of the British variety, kennel clubs will accept any variety of color between gold and cream, but dogs with a red or mahogany coat are disallowed. In the States, kennel clubs will allow a red or mahogany coat for the American variety. Thus, if you come across a dog with a darker coat, you can rest assured that it is not a registered English retriever.
Another difference between the two breeds is the shape of the eyes. English retrievers have round, dark-colored eyes; whereas, their American counterparts have slanted eyes. This is more of a subtle difference between the two breeds, but once you learn what to look for, it should be recognizable—not necessarily as recognizable as a dark color, but still noticeable.
British retrievers tend to be shorter than the American type. Males are between 22-24 inches at the shoulders and females between 20-22 inches. In the case of American retrievers, males stand between 23-24 inches and females between 21.5 and 22.5 inches. These are subtle differences, but they can make a difference when trying to get a dog registered.
The topline of a dog refers to the spine between the from and hindquarters of a dog. In the case of a British golden retriever, dogs should have a level topline. The American breed allows a subtle slant from the front to the rear quarters due a greater angulation in the hind legs.
These differences between the two breeds are subtle and should not affect the performance of the dog. On the other hand, whether you can specifically describe what makes one retriever look different than another or not, you should be able to see the difference. If you like the look of a British retriever and want to make sure you purchase the type of dog you are looking for, knowing what the specific differences are should help you to find an English retriever.