how to calculate transaction bytes of a x BTC? x=0.2
In the simplest typical case, you'll have one input and two outputs (the recipient, and change). So in=1 and out=2. According to the linked formula, the transaction size will be about 160+2*34+10 = 258 bytes. It does not depend on how many bitcoins you are sending.

However, if the money you are sending came from many different sources, you will have many inputs and the transaction will be bigger. Again, this does not depend on the amount of money, but on the complexity of your wallet's history.