Keto Calculator

February 28, 2018

Keto Calculator

According to my calculations, you need to methodically plan your nutrient intake for your keto adventure to be successful. It’s really very simple, let’s do the math.

Personal Goals

First of all you need to be clear on what your goals are for keto. This is because there are several variations of keto depending on what you want to achieve. Do you want to lose weight? Do you want to gain muscle? Do you want to prevent or treat a specific health condition?
It’s important to know why you are on keto as it affects the proportions of food you consume. Also, knowing why you are doing it will make it much easier to maintain long term motivation. Take a moment to think about why going keto is important to you and what benefits you are looking for.

The Standard Ketogenic Diet

The Standard Ketogenic Diet ( SKD), is the variation of keto that most people follow and depending on how much you eat it can be used to achieve significant weight loss. Unlike many diets which are ‘one size fits all,’ the keto diet is adapted to suit your unique body and personal goals.
To stay in ketosis you need to keep your carbs very low, get most of your fuel from fat, and eat enough protein to meet your body’s needs, but no more. The exact amount of fat, protein and carbohydrate you eat depends on your current weight and height, your activity levels and your keto goals, (for example weight loss).
Once you know this information you can use an online Keto Calculator to work out your body fat percentage, your metabolic rate and your macros. Macros means ‘macronutrients.’ This is the nutrition you need most of (fat, protein and carbs), compared to ‘micronutrients’ which refers to vitamins and minerals that you only need in very small amounts.
For body fat you can get a direct measurement. Using scales which have this feature either at home or in your gym or pharmacy or you can allow the keto calculator to estimate it based on your height and weight (which is usually pretty accurate unless you have a lot of muscle!)

Measuring Up

Let’s imagine the following, basic information:
Amy is 38 years old
She is 5 ft 7 inches and weighs 198 lbs
Her body fat percentage is 44.6%
Her goal is to lose 50lb
The calculator uses this basic information and determines that Amy’s Basal Metabolic Rate is 1607 calories. The Basal Metabolic Rate (or BMR) is the amount of energy she needs to consume daily to stay the same weight. This assumes she doesn’t exercise.
Next we tell the calculator that she is ‘lightly active’ and we get a new figure for the actual amount of calories she uses on a daily basis. Amy’s calculated daily energy expenditure is 1982 kcal, this means if she does the same amount of exercise as normal and consumes 1982 calories then she will stay the same weight. But, if Amy eats less than 1980 calories, she will lose weight. Pretty straightforward, right?

Macronutrient Calculations

The next step is to work out exactly how many grams of carbs, fat and protein she needs to eat per day to reach her calorie targets. Most calculators ask how many carbs you want to consume, usually between 20g and 30g. We suggest starting with 20g per day. This ensures you will definitely be in ketosis and gives you a little leeway if you forget to count something like the carbs in your carrots!
Next the calculator will work out how much protein you need based on how much you exercise.
When we exercise we break down and build new tissue. This means if you are currently sedentary you will need less protein. But as your health improves you may want to add more movement to your day, so you will need to increase your protein intake. For Amy, being ‘lightly active’, her protein requirement is 0.8g per lb of body weight, which equals 89g.
The final macro we need to calculate is fat. It is fat that gives you control and flexibility. You choose how much of a calorie deficit you want. The deficit is how many calories less than your calculated ‘daily energy expenditure’ you eat. When you eat less than you expend, you burn stored fat, simple as that!
If there is no deficit, then weight will remain the same.
If your deficit is only small, like 10% you will lose weight slowly. If your deficit is very big, like 30%, you will lose weight quickly but will find the diet much more difficult to stick to. So you need to find the sweet spot for you depending on how much weight, if any, you want to lose and how much of a calorie restriction you think will work for you.
If we assume the sweet spot for Amy is 22% (fast weight loss with moderate difficulty), the macros are as follows:
20g Carbs which is 80 kcal (representing is 5% of the total calories)
89g Protein which is 356 kcal (representing 22% of the total calories)
123g Fat which is 1108 kcal (representing 73% of the total calories)

Making Adjustments

Some calculators will even show you projected weight loss or weight gain over time. This means you can adjust your figures to suit specific goals, for example if you want to lose weight for a specific event like a wedding. For Amy it will take her 13 months to lose the 50 lb that she would like to. However, things change! She might start doing more exercise, or find that the deficit is too much to start with. Using a keto calculator is a great way to know you are eating the right amounts of fat, protein and carbs for your
body’s needs.
However, it is quite a technical way of planning your meals! It is a great way to begin your keto journey, and get confidence with your new eating habits. But after a relatively short period of time most people find they become more comfortable with the diet and are able to adjust their intake based on how their body feels. You will develop and intuition and understanding of what works for you and be able to adapt accordingly.
It’s important to recalculate, or reconsider, your macros when you make changes to the amount of exercise you are doing or after losing significant weight. One of the most common keto mistakes is not calculating your macros effectively which can result in dipping in and out of ketosis or feeling unsatisfied, both of which should be avoided. As you likely already know, the key to keto success is planning!


  • Know your goals as they determine how much food you consume
  • Use online keto calculators to work out how much of each macronutrient to consume daily
  • Planning is key and you may need to make macro adjustments as you progres
  • Ensure you take movement and exercise into account and don’t try to restrict too much too soon