We all know that hummingbirds are tiny, but have you ever considered just how tiny they really are? Have you ever wondered how much do hummingbirds weigh? The answer to this question depends on which species of hummingbird to which you are referring. The smallest hummingbird is the bee hummingbird which only weighs a little less than two grams. The largest hummingbird is known as the giant hummingbird and it weighs between 21 and 23 grams. According to hummingbird expert Laura Erickson, you could mail nine or ten hummingbirds with a single stamp! This should help give you some idea just how extremely tiny hummingbirds are.