Is 20 lbs to much for a miniature schnauzer to weigh?

No. This weight is perfectly normal for a miniature schnauzer. If your schnauzer gets overweight, take him/her for a run or a walk daily and only give him/her treats or "cookies" when they "do their jobs" outside. Only feed them at about 8:00 in the morning and at 6:30 in the evening. They can gain weight easily, so make sure they don't get excessive amounts of treats. Nope. . . . This is the weighs the adult Minature Schnauzer weighs. . I have a Minature Schnauzer and she is 17 pounds and she is only 1 1/2 years old so yeah this is a good weight for the Minature Schnauzer . . :-)