I have owned two leopard geckos for a lil over a year now and i'm not understanding why they are still small and skinny i feed them a dozen a week each and they seem to not grow i'm confused they have calcium powder and drink bottled water and they lady i get the crickets from said they should be pretty big by now i'm not sure whats going on or if someone can answer this question that has more experience than i do.

How big is the tank?

It doesn't sound like you are feeding them enough. My adult Leo eats about 5 crickets every other day. About 20-25 crickets a week. Not enough food could also be stunting them as well as bad nutrition.

A note to the other person. Fish do not grow to the size of
the tank. The tanks stunts their growth and greatly reduces their life span.

I have a leopard gecko
I have a 2000 gallon pond with 15 goldfish
Research

reptiles dont stop growing with to small of tank. That why you see burmese pythons 10 + feet in a simple 20 gallon tank. they keep growing with proper care. a dozen a week? seriosuly? i have 20 now tho 4 are rescues and very small (one has MBD) all the others eat atleast 40 bugs a week EACH . crickets, raochs, mealworms, super worms, butter worms, and wax worms. They need more food the 4 rescues were all given to little, 2 without calcuim, and suffered from it ... i highly dout they will grow and i dont think your's will at a year + there almost done growing ... but give them more food and house them seperately. Once they get stunted like that they begin fighting for food so for the sake of them house them alone (they dont want to be with eachother nor need to be; reptiles dont get lonley) be suer to dust 2-3 times a week withOUT D3 and once a week with D3 and you may see some improvement ...

own 20 geckos, 5 rescues, 4 that were food deprived,

Well adult females are typically 7 to 8 inches, and males are 8 to 10 inches and that's the biggest. They normally never get to the biggest size possible. But if they are still small knowing how big they get it could be that you have too small of a tank. Try getting a bigger tank. Fish are the same way they will only grow big enough to have enough room to live.

Can't help you with your question I'm afraid, but to the two people above, yes fish will get stunted in a tank too small for them, but reptiles will grow regardless the size of the tank, it does not stunt their growth. Fish release a hormone which prevents them growing any larger in their enclosure, reptiles do not.