Keto Macros Calculator
A ketogenic diet is characterised by very low carbohydrate intake, moderate protein, and high fat, producing a metabolic state called ketosis in which the body uses fat and ketone bodies as its primary energy source. The classic therapeutic ketogenic ratio is approximately 5% carbohydrates, 20% protein, and 75% fat by calories. This calculator applies your chosen keto percentages to your daily calorie goal, converting each macro share into grams using the standard Atwater caloric density factors: 4 kcal/g for carbohydrates and protein, 9 kcal/g for fat. You can use the default 5/20/75 split or enter your own percentages as long as they sum to 100.
Keto macro formula
Carbs (g) = Calories * (Carb% / 100) / 4
Protein (g) = Calories * (Protein% / 100) / 4
Fat (g) = Calories * (Fat% / 100) / 9
Standard keto split: 5% carbs, 20% protein, 75% fat. All percentages must sum to 100. Carbs and protein supply 4 kcal/g; fat supplies 9 kcal/g.
Ketogenic diet macro guidelines
- Classic keto (5/20/75): used therapeutically and for strict weight loss protocols.
- Modified keto (10/20/70): allows slightly more carbs, often preferred for long-term sustainability.
- Targeted keto: add carbs (25-50 g) around workouts while staying keto otherwise.
- Keep daily net carbs below 20-50 g to reliably maintain nutritional ketosis.
- Adequate electrolyte intake (sodium, potassium, magnesium) is especially important on a ketogenic diet due to increased urinary excretion.
Keto macros calculator: frequently asked questions
What is the standard keto macronutrient ratio?
A classic ketogenic diet typically derives approximately 5% of calories from carbohydrates, 20% from protein, and 75% from fat. This ratio limits carbohydrate intake enough to induce and maintain ketosis, a metabolic state where the body burns fat for fuel.
How many grams of carbs per day is keto?
Most ketogenic protocols target 20-50 g of net carbohydrates per day. At 2,000 kcal with a 5% carb ratio, that equals approximately 25 g of carbs per day, which is well within the ketogenic range.
Why is protein kept moderate on keto?
Excess protein can be converted to glucose through gluconeogenesis, potentially disrupting ketosis. Most keto protocols recommend 0.8-1.2 g of protein per pound of lean body mass to preserve muscle without exceeding the glucose-generating threshold.
Can I customise the keto macro percentages?
Yes. This calculator lets you enter your own percentage split. Common variations include therapeutic keto (80-90% fat) used for epilepsy under medical supervision, and modified keto (10-15% carbs) for athletes needing more glycogen.
What is the difference between net carbs and total carbs?
Net carbs are total carbohydrates minus dietary fiber (and sugar alcohols in some counting methods). Fiber is not digested and does not raise blood glucose, so it is excluded from the ketogenic carb limit. This calculator shows total carb grams; track fiber separately.
Official sources
- USDA Dietary Guidelines 2020-2025: DietaryGuidelines.gov.
- NIH National Library of Medicine: Ketogenic Diet (StatPearls).
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.