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How Many Calories Do I Need a Day?


How many calories do I need a day is a common question that I get asked often. The answer is not a ‘One size fits all’ one because a lot of factors come into play.

You will need to do some calculation here, to get it right for you…and I mean "you" because everyone is different.

The amount of calories you need daily depends on such factors as your age, sex, height, your current weight, and how physically active you are.

However there is a formula that takes all these into consideration to arrive at a final figure for you and you only.


First, we need to establish your Basal Metabolic Rate (BMR). This is essentially what your body will need in order to function routinely. In calculating 'how many calories do I need a day', you need to use a formula based on the Harris-Benedict Principle. This formula takes the factors I mentioned previously into consideration.

Now here is the formula. I know it is a pain but you will need to get a pen, paper and calculator to do this and get it right once and for all. Let’s get the brain into gear and do some maths.


It's going to be let's do it!

By the way, you can get conversion tools online like converting kg to pounds or metres to inches. Just search online for whatever conversion you want to do.





BMR for Women
Here is the formula to do the BMR calculation and eventually get the figure for the query - how many calories do I need a day.


 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)

Okay, here is an example just to bring it home nice and easy.


You are a woman, aged 40, 70 inches tall and weighs 142 pounds, your BMR will be calculated like this:

655 + (4.35 x 142) + (4.7 x 70) – (4.7 x 40)
655 + 617.7 + 329 – 188
BMR= 1413.7


There is a further step to finishing the calculation which is based on how active you are but it is very simple. Honest. You just choose from below your level of daily activity and multiply as indicated below.

  • Sedentary = BMR x 1.2
  • Lightly Active = BMR x 1.4
  • Moderately Active = BMR x 1.6
  • Very Active = BMR x 1.7
  • Athletic = BMR x 1.9

Let’s say our lady from the previous example is moderately active, then her final figure will be 1413.7 x 1.6 = 2262 Calories per day. Yes, this what her body needs per day to function.
The formula to calculate how many calories do I need a day for men is slightly different but the principle and method are the same.

BMR Formula for Men below:

Here is the formula for calculating BMR for men from which you also derive how many calories do I need per day.


66 + (6.3 x weight in pounds) + (12.9 x height in inches) - (6.8 x age in years)

Just as it is for women, after you have arrived at your BMR, you will need to incorporate your level of activity similar to the example above to arrive at an answer.


How many calories do I need a day to survive?
The final figure you derive from the BMR formula above including the activity component is how to arrive at the answer to the question of how many calories do I need per day to survive….and that is what you need daily to maintain your current weight, if you are happy with it.


How many calories do I need to gain weight?
If you want to gain weight (of course there are individuals who want to gain weight too), all you need to do is consume 3,500 calories of food more than your usual caloric needs to gain 1 pound of weight.

Your calorie intake must exceed your calorie output.

If your caloric figure is say 2100 Calories per day. Do the calculation above first please to get your unique caloric requirement figure.


Instead of consuming 2100 calories per day, you consume 2600 Calories per day (an extra 500 calories per day). In 7 days you would have consumed 3,500 extra calories in total, on top of your daily requirement in that week. This value will enable you add on 1 pound of weight.

Of course you can do this as quickly and as slowly as you wish. It depends on how much weight you need to add on and how fast you want to accomplish that goal.


Calories needed to lose weight
Now that we've answered the question of how many calories do I need a day, you want to know the answer to the next question which is, ‘how many calories do I need to loose weight’. Visit that link for more information and learn a simple way to go about calculating this all important figure so you can start the journey today.


Loose weight