Hi Shalimar
http://keto-calculator.ankerl.com is a site that Igor often recommends – I have used it and thought it was useful.
You put in your personal details , target calories, carbs etc, and it comes up with recommended fat and protein
When I was aiming for 50g of carbs, it came up with 45g protein and 50g fat (or vice versa) – I mentally remembered as pretty much 50/50/50. TBH, if I am counting carbs and calories, I tend to stick to BSD principles and let the other stuff fall out by itself.
You can then use the targets that the keto site gives as goals in Fat Secret/My Fitness Pal or whatever you are using to track.
Personally, with any recipe, I always calculate the calories, carbs etc from the ingredients that I use – I often vary recipes that I use, and invariably adjust the quantity that I make.