text: what's the average penis size?   the average measures are: erect length  modest =  14 cm. (5.4") average= 16 cm. (6.3") erect circumference modest = 11,5 cm. (4.5") average= 12,5 cm. (5.0") while sex even is possible with shorter penis. just enjoy your body as it’s. good and satisfactory sex isn’t measured by penis length.