i checked my baby’s growth percentile on two different websites and it came diff..?

one and other is babycentre About.com the stats are length = 75 cm and the weight is 19.8 pounds. i 'M he is concerned about the very small …. the weight of guuys makes u think of this? The center of the child is giving the percentiles as follows length = between 50-75% = weight between 25-50% Whereas on About.com its like 40% for the length 25% by weight which belive. make some of u knw where I can load programs object the table. . that the most authentic of the percentile of development. sorry I forgot to mention that it is turning 1 years October 13