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Keto Calculator
Use this free keto calculator to find your daily calories and keto macros in grams. Enter your age, sex, height, weight, activity level, and goal, and it works out your BMR with the Mifflin-St Jeor equation, then splits your calories into fat, protein, and carbs at the standard 70/25/5 ratio — plus two alternate splits to compare.
Calories are rounded to the nearest whole number and macros to the nearest gram. Fat has 9 calories per gram; protein and carbohydrate have 4 calories per gram.
Your macro split
The chart shows the standard 70% fat, 25% protein, 5% carbohydrate split. The table below the result shows two more splits so you can compare them.
How it works
A keto calculator turns your body measurements into a daily eating plan for a ketogenic diet. Keto means eating very few carbohydrates, a moderate amount of protein, and most of your calories from fat. When carbs stay low for days at a time, the body starts making ketones from fat and using them for fuel. That switch is the whole point of the diet, and it only works if the daily carb limit is genuinely small — usually under 30 to 50 grams a day — which is why guessing does not work well and a calculator helps.
The first step is your basal metabolic rate, or BMR. That is the number of calories your body burns in a day if you did nothing at all — just breathing, keeping warm, and keeping your organs running. This calculator uses the Mifflin-St Jeor equation, which is the formula most dietitians and nutrition researchers use today because it fits real measured metabolic rates better than older formulas. It takes your weight, height, age, and sex, because muscle burns more energy than fat, taller and heavier bodies burn more, and metabolism slows slightly with age.
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Next, the calculator multiplies your BMR by an activity factor to get your total daily energy expenditure, or TDEE. A desk worker who rarely exercises multiplies by 1.2, while someone who trains six days a week multiplies by 1.725. Then your goal adjusts the total: losing weight subtracts 500 calories a day, which works out to roughly one pound of fat loss per week, maintaining keeps the TDEE as it is, and gaining adds 300 calories a day for a slow, steady surplus.
Finally, the target calories are split into macros. The standard keto split is 70% of calories from fat, 25% from protein, and 5% from carbohydrate. Fat has 9 calories per gram, while protein and carbohydrate each have 4 calories per gram, so the grams come from dividing each share by its calories per gram. The calculator also shows two alternate splits: 75% fat, 20% protein, 5% carbs, which is stricter and suits people who want deeper ketosis, and 65% fat, 30% protein, 5% carbs, which keeps more protein for people who lift weights and want to protect muscle. Carbs stay at 5% in all three splits, because that is the part that keeps you in ketosis.
A few practical notes make the numbers easier to live with. Weigh foods with a kitchen scale for the first two weeks, because eyeballing a tablespoon of oil or a serving of nuts is usually wrong by a wide margin. Drink enough water and keep salt in your food, especially in the first week, when the body sheds water and many people feel tired or headachy — the so-called keto flu.
Worked example
Take a 35-year-old man who is 180 cm tall, weighs 85 kg, exercises three to five days a week, and wants to lose weight. Here is exactly what the calculator does with those numbers.
Step 1 — BMR. Using the men's formula: 10 × 85 = 850, plus 6.25 × 180 = 1,125, minus 5 × 35 = 175, plus 5. That gives 850 + 1,125 − 175 + 5 = 1,805 calories per day at complete rest.
Step 2 — TDEE. Moderately active means multiplying by 1.55, so 1,805 × 1.55 = 2,798 calories per day to maintain his current weight.
Step 3 — Goal. Losing weight subtracts 500 calories, so his daily target is 2,798 − 500 = 2,298 calories.
Step 4 — Macros at the standard 70/25/5 split. Fat: 70% of 2,298 is 1,609 calories, divided by 9 calories per gram = 179 g of fat. Protein: 25% of 2,298 is 575 calories, divided by 4 = 144 g of protein. Carbs: 5% of 2,298 is 115 calories, divided by 4 = 29 g of carbs.
Step 5 — Compare the other splits. At 75/20/5 he would eat 192 g of fat, 115 g of protein, and 29 g of carbs. At 65/30/5 he would eat 166 g of fat, 172 g of protein, and 29 g of carbs. Enter the same numbers — age 35, male, 180 cm, 85 kg, moderately active, lose weight — and the tool shows exactly these results, with the donut chart showing 70% fat, 25% protein, and 5% carbs.
FAQ
How many carbs can I eat on keto?
Most people stay in ketosis at 20 to 50 grams of net carbs a day, and this calculator's 5% share usually lands near 25 to 30 grams for a typical adult. The exact limit varies with body size and activity, so treat the calculator's carb number as a daily ceiling and keep it steady for at least two weeks before judging how you feel.
Is 70% fat, 25% protein, 5% carbs the only keto split?
No. It is the standard starting split, but many people do better on 75% fat and 20% protein if they want stricter ketosis, or 65% fat and 30% protein if they train hard and want more protein to protect muscle. This calculator shows all three splits side by side so you can pick the one that fits your training and appetite.
How fast will I lose weight on keto?
A 500-calorie daily deficit works out to roughly one pound of fat loss per week, but the first week is usually faster because the body sheds stored water as carb stores empty. That early drop is mostly water, not fat, so judge progress by the trend over four weeks, not by any single weigh-in.
Do I need to count calories on keto, or just carbs?
Counting only carbs is enough for some people, because fat is filling and appetite often drops. But calories still decide whether you lose, maintain, or gain weight — keto changes which foods you eat, not the laws of energy balance. If your weight stalls for three weeks, check your total calories first.
Can I do keto if I am vegetarian?
Yes, with more planning. Eggs, cheese, paneer, tofu, tempeh, nuts, seeds, avocado, and olive oil can cover fat and protein, but hitting the protein target without meat takes deliberate choices at every meal. A vegetarian keto plan usually needs a protein shake or extra eggs to reach the grams this calculator suggests.