Is 6 inch penis small for a 15 year old?

No. It's maybe a little bit bigger than average. The normal size is about:

* Before puberty, between 3 and 4 inches erect (8 - 10 cm). * After your puberty growth spurt, maybe 4 - 6 inches (10 - 15 cm). * It will keep growing through puberty till you are 18 or 19 years old.

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What_is_the_average_size_of_a_penis
No!