Fat Calc    

Realistic Weight Loss Goal Calculator

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Realistic Weight Loss GoalCalculate energy and time to weight loss.

How much weight is realistic for you to lose and how many Calories (kilocalories) should you be consuming?

Use this calculator to find a realistic weight loss Calorie deficit plan that's right for you. You choose how much you want to weigh. The calculator will generate a table that lists daily Calorie intakes along with the time it would take you to reach your weight goal for each of the Calorie intake levels.

Calories are shown in 50 Calorie decrements, beginning with the daily Calories it takes to maintain your current weight. For each 50 Calorie decrease in daily energy intake, you can see how long it would take, in days, months or years, to reach your target weight. You can then choose and stick to a daily Calorie intake level that is doable by you and know how long you need to keep at it.

About the Calculations

Calculations incorporated into this app are based on the model developed by Kevin Hall, Ph. D., and a team of researchers at the National Institute of Health. It is a much more accurate model in determining energy expenditure and energy requirements for the purpose of weight management. It challenges the 3500 Calories per pound rule by taking into consideration the physiological changes that take place during weight loss. This includes changes in body fat, muscle mass, the thermic effects of feeding, glycogen and sodium intake.


Enter your body parameters, physical activity level, your current or starting weight and your weight goal. If you don't know your physical activity level, click the Estimate button to calculate an estimation. It will pop up a form where you select from activities at work and during your leisure time.

Click Calculate to generate a table of daily energy intake levels vs time to weight goal. Consult a doctor for guidance and support if you are considering a diet of less than 1,000 Calories (4184 kJ) per day. Food group targets and nutrient recommendations will not be met below that level.

Related Site:

  1. Quantification of the effect of energy imbalance on bodyweight.
    Hall KD, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA.
    Lancet (2011 Aug 27) 27;378(9793):826-37.