Keto Macro Calculator
A ketogenic diet flips the standard macro ratio on its head: instead of carbohydrates being your primary fuel, you restrict carbs to 20–50 g/day and rely on dietary fat for 70–75% of your calories. This forces your body into nutritional ketosis, where it burns fat (and produces ketones) as its primary energy source. Getting the macros right is critical — too many carbs and you fall out of ketosis; too little protein and you risk muscle loss. This keto macro calculator takes your calorie target and applies a ketogenic macro split: 70% fat, 25% protein, 5% carbs. You can fine-tune these percentages, but staying within the keto window (carbs under 50 g/day) is enforced by the calculator.
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Example Use Cases
A 2,000 kcal keto diet: 156 g fat (70%), 125 g protein (25%), 25 g carbs (5%). The carb target of 25 g fits within the strict keto threshold of <50 g/day.
A 1,600 kcal keto diet for weight loss: 124 g fat, 100 g protein, 20 g carbs. The protein target of 100 g may feel low for active individuals — adjust % upward to 30% if needed (and reduce fat accordingly).
How to Interpret Your Results
On keto, the most common mistake is eating too much protein relative to fat (which can suppress ketosis via gluconeogenesis) or not eating enough protein (which causes muscle loss). Aim for at least 1.2–1.7 g/kg protein; the rest of your non-carb calories should come from fat.
Frequently Asked Questions
Methodology & Limitations
Formulas Used
Macro grams are derived from total calories: **Protein (g) = (calories × protein%) ÷ 4**, **Carbs (g) = (calories × carb%) ÷ 4**, **Fat (g) = (calories × fat%) ÷ 9**. Preset ratios are based on general sports-nutrition guidelines.
Page-Specific Notes
Default keto split: 70F/25P/5C. The calculator enforces a maximum of 50 g carbs/day; if total calories push carbs above 50 g at 5%, the percentage is capped and remaining calories shift to fat.
Limitations
Optimal macro ratios vary by individual and depend on factors like training volume, body composition, metabolic health, and food preferences. Use presets as starting points and adjust based on your response over 2–4 weeks. Consult a registered dietitian for medical nutrition therapy.
Sources & Citations
- Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
- Helms ER, et al. Evidence-based recommendations for natural bodybuilding contest preparation. J Int Soc Sports Nutr. 2014;11:20.
Medical Disclaimer: This calculator provides estimates based on published formulas and is not a substitute for professional medical advice. Always consult a qualified healthcare provider before making changes to your diet or exercise routine.
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