I have a 15 week old border collie male. How tall and heavy should it be. he weighs aroung 10 kgs.?

He will be a medium size dog. Not real big. Can't give you an exact weight cause all dogs are different I am guessing around 35-40 lbs would be a close weight to go on. But I have had them get bigger. It also will matter how much exercise your dog gets. He will get about knee high may be a little taller, may be a little shorter measured from his back down.