About the Keto Calculator
Keto Calculator estimates your daily calories and the grams of fat, protein and net carbs for a ketogenic diet. It works out the calories you burn with the Mifflin-St Jeor formula and your activity level, adjusts them for your goal (lose weight, keep weight or gain), sets net carbs to a low amount you choose (such as 25 g), sets protein from your body weight and fills the rest of the calories with fat. The answer shows the grams and the percentage of calories from each. It is an estimate and not medical advice.
Updated October 2026
How to use the Keto Calculator
- 1Choose your sex and enter your age, weight in kg and height in cm.
- 2Pick your activity level and your goal.
- 3Choose your daily net carbs (20 to 50 g is typical) and protein per kg.
- 4Read the daily calories and the grams of fat, protein and carbs.
- 5Copy the numbers into your food tracker.
How the numbers are built
First the page estimates your basal metabolic rate, the energy your body uses at rest, with the Mifflin-St Jeor formula. It multiplies that by an activity factor to get the calories you burn in a day. The goal then changes the target: 15% fewer calories for steady weight loss, equal for maintenance, 10% more for gain, with a floor of 1,200 kcal.
Carbs, protein and fat
Carbs are fixed first because they are what defines keto. Protein is set per kilogram of body weight to protect muscle, and the remainder of the calories becomes fat. With fat at 9 calories per gram and carbs and protein at 4, the grams you see add back up to your calorie target.
- Net carbs: 20 to 50 g
- Protein: 1.2 to 2.0 g per kg
- Fat: the rest, often 65% to 75% of calories
Practical tips
Weigh and log food for a couple of weeks to learn what 25 g of net carbs looks like. Drink water, add salt and eat enough vegetables, because the first week can bring headaches and tiredness, the so-called keto flu. If you feel unwell, speak to a doctor.
Related tools
Compare with the Macro Calculator, the Calorie Calculator and the TDEE Calculator. The BMI Calculator and the Protein Calculator add context for your body size.
Features
- Mifflin-St Jeor energy estimate
- Goals for losing, keeping or gaining weight
- Net carbs and protein you set
- Fat fills the remaining calories
- Percent of calories from each macro
- Private: nothing is uploaded
Frequently asked questions
What is a keto diet?
A very low carbohydrate, high fat diet that makes the body burn fat and produce ketones for energy. Most plans keep net carbs between 20 and 50 grams a day.
What are net carbs?
Total carbohydrates minus fibre, and sometimes minus sugar alcohols. Net carbs are the ones that raise blood sugar, so they are the number to count on keto.
How is protein set?
From your body weight, 1.6 g per kg by default. Too little protein can cost muscle, and very high protein can be turned partly into glucose, so a moderate amount is common.
Why is fat so high?
On keto fat supplies most of your energy, so after protein and carbs, the rest of your calories come from fat, often 65% to 75%.
Is a calorie deficit still needed to lose weight?
Yes. Keto changes what you eat but weight loss still depends on eating less energy than you burn, which is why the goal option reduces calories by 15% or 20%.
Who should not try keto?
People with pancreas, liver, kidney or gallbladder problems, type 1 diabetes, a history of eating disorders, and those who are pregnant or breastfeeding should not start without a doctor. People who take diabetes or blood pressure medicine need supervision.
Is the result exact?
No. Formulas estimate the average person. Track your weight for a few weeks and adjust.
Is my data stored?
No. It is calculated in your browser.