I've got about 5 months to lose 40lbs, are there any calorie calculators to determine how much I should eat?

I'm living with a friend right now, and I have about 5 months to move out. I've got too many bills to pay to get my own place and support myself. I make $10 an hour so that's not going to happen. I'm going to join the military when that time comes around. I need to have a healthy BMI to get in. My friend has a gym membership and I got to go in for free to find out my perfect BMI weight. I'm 5'3 and 165lbs and I should be 125 by the time I join. Is there a calorie calculator that will tell me how much to consume a day to reach that weight at that time? I do have a couple of other friends that would let me stay for like a week or two, I don't really want to do that if I don't have to.