This is hard to answer, because it really depends on your current weight, height, age, health, and activity level. They used to recommend 1200 calories per day to lose weight at a safe level, but many doctors are now recommending 1500. Other people lose better at 2000 calories. Your best bet is to pick a mid range, try it for a few weeks, then adjust as necessary. It's important not to go too low, because this can alter your metabolism and make it harder to lose weight, and much more difficult to keep it off.
I personally always did best if I consumed between 1600 and 2000 calories, spread out between 3 meals and 2 snacks. I also added exercise to my routine. Without it, the weight loss was extremely slow, even with fewer calories.
You have to experiment to find what works best for you, because you are unique