I have a question about calorie restriction

I’m doing the calorie restriction thing. I’m consuming 1200 calories a day, but I just pulled that number out of the air. I’ve read a couple books on the subject and looked around on the internet, but I haven’t found anything that says how to calculate the amount of calories I should be consuming to get the max benefits from calorie restriction. I figured 1200 calories is more then 50% of a 2500 calorie diet. That’s calorie restriction. But is it enough to get all the suggested benefits.

Use an online calculator to determine your BMR caloric expenditure, from that point, initiate a deficit of 500 cals/day.