It depends on your measurements. Are you talking about inches, or centimeters, and it also depends on the size and age of the person. What would be large for a 4 year old would be small for a 34 year old.
It depends, on many things, it depends on your height, your bones, your body fat. It also depends on the region where you live. If you are 5'6'' with thin bones and 16inch arms with 4% bodyfat, you gonna look bigger than someone who is 6'3'' with big bones, 18 inch arms, with 30% bodyfat. For average height 5'6'' - 5'11'', and 15 or 20% bodyfat at the most,with 16.5''-18'' you look big.
You should compare it to your triceps ... the biceps should compose 1/3 of your arm size for balance. If not, you need to relook at your training.
It depends on your age and fitness. 15 inches would be big for a boy but not that big for a man with muscles.
1 inches
Georgr St Pierre's biceps are 15 inch's around
Massive
21
16.5 inches
21 inches
10 inches
56 yo
Triple h has big biceps. its biceps size is 32 inches. he has his name in guineas world records 2001.he is also known as big biceps(trippie). he also defeat khali in arm wrestling who,s biceps size is 30 inches. only 2 inches less. if you have more size in biceps than you will win
P90X trust me it works
the weight lifting machines
bring the gym to you.