You can use something like that to check the IVs of your Pokemon by entering it's stats at different levels. It will give you a range if you just enter one level (unless the Pokemon's level 100) and that range will start to shrink as you enter more levels. You can find your Pokemon's IVs exactly just by having a level 30 Pokemon and a couple Rare Candies.
3DS FC: 5257 - 9998 - 2632 Pokemon Y Name: Benjamin
I know the IV checker tells you if your IV's are 31 or if they're 0, but I see people trading pokemon with 29 IV's in stats aswell. How do people know this? Am I missing something from the IV checker?
Well you can calculate if and yes there is a formula should be on seribii but if you are seeing very precise numbers like 31/31/22/4/31/30 then most people are probably just instachecking, its 100% accurate and its what I use.
Im not here to condone or tell you how to use it, its just on of the two methods to get numbers that are not 31 or 0, but when you include wrong calculations and throwing evs into the mix, chances are any calculated stats will never be 100%, thus the reason why ~ is used as an approx stat.
IGN:Sherlock FC: 2595-1212-5793 Safari: Rydon Rock Type