A study published in the September 1996 Journal of Urology concluded that average erect length was 12.9 cm (5.08 in) (Measured by staff).
The erect penis length is about 7 to 8 inches.
Your age and the stage of puberty you are in will have a big effect on the length of your penis. The average length of an adult erect penis is 6 to 7 inches long. There isn't an average length for flaccid (limp or soft) penises because their length can alter with the temperature and with your emotional state.
For adults (who are done with puberty), the average penis size when erect is 5-6 inches.
This is about, or just over the average size erect penis for your age.
An erect adult penis averages 5-5.5 inches in length. If your penis is already 8 inches long, I would assume it has reached its maximum growth.
The national average erect penis length is 5 1/2 inches, so you are about as normal as you can get.
The average length of a seven-year-old boy's penis is between 2 and 2.8 inches when erect.
The average length for an erect adult penis is 6 to 7 inches so anything longer than this would by definition be considered to be large.
Average size of an erect male penis is around 6 inches, so you're average. Plus the depth of the vagina is about 4 inches if that makes you feel better :P
Your measurements would put you pretty much in the average range for length and girth for your age. An adult erect penis has an average length of 6 to 7 inches and an average girth of 4 to 5 inches, you probably still have a bit more growing to do before you complete puberty so you are bang on target to fit in the average range. thats a lie
Typical length from the knot to the tip is around 8 inches when fully erect.
The average length of an erect adult penis is 6 to 7 inches so 6 inches is well big enough for anything you want to use it for. But please realize, Width does play an important role in sexual pleasure.