I think some of the confusion is about the difference between calories and kilojoules.
I also think that Sharrelle might have meant to write cals instead of kj as well.
Alan Borushek's 2012 Calorie Fat & Carbohydrate Counter book suggested Calories for weight loss in women as:
Non-active 1000-1200cal
Active 1200-1500cal
Very Active 1500-1800cal
(1 Calorie = 4.2 Kilojoules)
This is for a loss of between 0.5kg and 1.0kg per week.
He also adds that for lactation you should add up to another 500 calories to the number.
Please be aware that most people don't lose weight consistently each week. Usually it cycles between a "good" week and a week with a smaller loss. Also note that you will lose more when you start (some of it is fluid loss and some of it simply because you have a lot more to lose) than at the later stages of your weight loss. For example, my average weekly loss for the first month was 2.3kg per week but my average weekly loss over the entire 60 weeks it took me to reach goal was 1.4kg.
In the end - the proof is in the pudding. Try at one number - and then adjust accordingly.
I myself never bothered counting calories (or kilojoules)...I just started by reducing my serve sizes by half (figured I was twice the size I should have been...so I must be eating twice the amount I should have).
I hope this has been helpful to you.
Kim