How to use the keto calculator
- Enter your details. Pick US or metric units and add your sex, age, height, weight and activity level.
- Choose your goal and carb limit. Lose, lose slowly or maintain, then a daily net carb limit from 20 g (strict) to 50 g (lazy keto).
- Pick a food preference. Everything, no pork or vegetarian, which changes the 7 day meal plan.
- Read your macros and plan. See your daily calories, net carbs, protein and fat in grams and percent, then follow the meal plan.
What are keto macros?
A ketogenic diet keeps carbohydrates so low, usually 20 to 50 g of net carbs a day, that your body switches to burning fat and producing ketones for fuel. Protein stays moderate to protect muscle, and fat makes up the rest of your calories. A typical split is about 5 to 10 percent carbs, 20 to 25 percent protein and 65 to 75 percent fat.
How the keto calculator works
- Calories: we estimate your maintenance calories with the Mifflin St Jeor equation and your activity level, then apply your goal. We never go below 1,200 kcal for women or 1,500 kcal for men.
- Carbs: set by your chosen daily net carb limit.
- Protein: about 1.4 g per kg of body weight, enough to preserve muscle without pushing you out of ketosis.
- Fat: whatever calories remain, divided by 9 calories per gram.
How to use the 7 day meal plan
The plan picks a breakfast, lunch, dinner and snack for each day from a library of simple keto meals, keeping each day within your net carb limit and avoiding repeats. Press shuffle for new ideas, and choose vegetarian or no pork if you need to. The carb counts are typical per serving estimates, so check labels and adjust portion sizes to land near your calorie target.
Worked example: 35, 5 ft 6 in, 165 lb, lightly active
A real run of the calculator for a 35 year old woman, 5 ft 6 in and 165 lb (74.8 kg), exercising one to three days a week, choosing to lose weight on the standard 25 g net carb limit.
| Macro | How it is set | Grams | Share of calories |
|---|---|---|---|
| Calories | Mifflin St Jeor maintenance (2,008) minus 20 percent | 1,610 kcal | 100% |
| Net carbs | Your chosen limit | 25 g | 6% |
| Protein | 1.4 g per kg of body weight (74.8 x 1.4) | 105 g | 26% |
| Fat | Fills the rest: (1,610 − 25 x 4 − 105 x 4) ÷ 9 | 121 g | 68% |
Protein is set first because it protects muscle while you lose weight, carbs are capped, and fat makes up the remaining calories. You do not need to hit the fat number exactly: it is a ceiling for satiety, not a target to force down.
Keto safety
Many people feel tired, foggy or headachy in the first week as the body adapts, often called keto flu. Extra water, salt, magnesium and potassium usually help. Keto is not suitable for everyone. Anyone with type 1 diabetes, kidney or liver disease, a history of eating disorders, who is pregnant or breastfeeding, or who takes medication for diabetes or blood pressure should only try it with a doctor's supervision, because medication doses may need to change quickly.
Want a less restrictive approach? The calorie calculator gives a balanced macro split, and the weight loss calculator shows a realistic timeline for your goal.
Sources: Mifflin St Jeor equation (1990); ketogenic diet reviews in StatPearls, NCBI; Harvard T.H. Chan School of Public Health nutrition guidance.
