How many calorie to lose weight?

In order to loose at least 1 kg of weight in a week you have to burn 3500 calories and reduce another 3500 calories in a week.So in total a negative balance of 7000 calories a week leads to 1 kg of weight loss.

To lose weight your calorie intake should be up to 1200-1500 calories depending on your goal,age,weight,height,sex and activity level.

Hey Arundhati..... Many more details are required to consider your question seriously for giving any useful answer......like
your height,surface area, weight ,your diet,nature of work,daily exercise.
How ever after deciding the weight to be reduced, how much to be allocated by each ,say,diet, exercise etc. to be worked out.
It should be a slow and steady reduction. Dont only go for dieting but try to include some exercises too so as to burn calories too.