While there is no definite answer to this question, there is a guideline that can help you determine how many calories you should eat per day in order to lose weight (or maintain your current weight).
It is called Ideal Body Weight (IBW) formula. If you are fit and healthy and you want to maintain your current weight, your IBW is your current weight. But if you want to lose weight, your IBW is your goal weight.
The formula is easy, just multiply your IBW by 14 and that gives you a guideline of how many calories you should eat per day.
Please know that this is a very rough calculation and it’s provided here without any guarantees. For a more accurate evaluation you need to have your metabolic rate evaluated by a professional.
Also, to lose weight it would be ideal if you maintain an exercise routine. A 30 minute walk two or three days a week will be very beneficial. Drink plenty of water and eliminate fast foods and sodas.
For a more in depth explanation or to check how to calculate your IBW check out this article.