Weight Loss Calculator

How long will it take you to reach your weight loss goal?


Drag the slider to adjust daily calorie intake.



Estimating Weight Loss

weight loss calculator

This calculator provides a basic assessment of the time taken to lose weight.

A calorie deficit can be obtained either by consuming less caloried-dense food, and/or by including exercise.

It's also important to note that as you lose weight, your body will require less calories for maintenance. You should update your weight loss estimation periodically as your weight changes to get the most accurate estimation.

A mixture of both diet change and increased exercise will bring the best results.

To calculate your optimal daily maintenance calories, use the calorie calculator.

What is a Calorie Deficit?

This is the difference between your normal maintenance calorie intake, and what you will be eating when following your new diet.

You normally consume around 2,500 calories per day to maintain your weight. If you drop to 2,000 calories per day as part of your new diet, you will have a deficit of 500 calories.

If you currently do no exercise, but begin 15 minutes of high impact aerobics per day (100 calories burned), then your deficit will become 600 calories.

Find out how many calories burned by exercise here.


Ensure you do not drop your food intake too low or too quickly.

This will not necessarily quicken weight loss, but will probably cause your metabolic rate to slow down - increasing your chances of gaining the weight back again!

First try taking 500 calories (or even 15%) off your current food intake - and track your results.

Humans Are Not Calculators

Humans are not robots, and everyone will obtain individual results. Weight loss plateaus can occur along the way, as our bodies can adapt to the changing food intake.

Research (of many other trials over the past 25 years) shows that a 15-week diet program will produce around 11kg (24.2 lbs) of weight loss. However, this is not maintained over the year, with some of the weight coming back on.

Read more about calories here.


  • Grodstein, F., Levine, R., Troy, L., Spencer, T., Colditz, G. A., & Stampfer, M. J. (1996). Three-year follow-up of participants in a commercial weight loss program: can you keep it off?. Archives of Internal Medicine, 156(12), 1302-1306. Link
  • Miller, W. C., Koceja, D. M., & Hamilton, E. J. (1997). A meta-analysis of the past 25 years of weight loss research using diet, exercise or diet plus exercise intervention. International journal of obesity, 21(10), 941-947. Link
Last updated 29 Dec 2014