Keto Calculator — Personalized Macros
Calculate keto macros free. Choose Standard, High-Protein or Modified keto. Mifflin-St Jeor formula with electrolyte recommendations and comparison.
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CalcVita. (2026). Keto Calculator — Personalized Macros. CalcVita. Retrieved October 16, 2026, from https://calcvita.com/en/calculators/keto
Suggested article
Keto Diet Guide: How Ketosis Works, What to Eat & Safety Tips
Understand how the ketogenic diet triggers ketosis, which macros to target, how to manage electrolytes, and what the science says about safety and effectiveness.
Read the full article →Quick Guide to the Keto Calculator
This keto calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR), then adjusts for activity level to find your Total Daily Energy Expenditure (TDEE). Choose from three keto presets — Standard (75/20/5), High-Protein (60/35/5), or Modified (65/25/10) — and apply a caloric deficit or surplus based on your goals.
How It Works
Your BMR is calculated using weight, height, age, and sex (Mifflin-St Jeor, 1990). TDEE multiplies BMR by your activity level. The calculator then distributes calories across fat, protein, and net carbs based on your chosen keto ratio. Ketosis typically requires keeping net carbs below 20-50g/day, shifting fat to your primary fuel source. A protein guardrail ensures at least 0.8g per kg body weight to preserve lean mass.
Interpreting Your Results
Fat provides sustained energy and satiety on keto. Protein maintains muscle and supports recovery. Net carbs should stay below the ketosis threshold (usually 20-25g for standard keto). During the adaptation phase (2-4 weeks), your body transitions from glucose to fat-burning. Electrolyte supplementation is crucial during this period to avoid "keto flu" symptoms.
Limitations
This calculator is not suitable for people with type 1 diabetes, kidney disease, liver conditions, or pancreatic disorders without medical supervision. Pregnant and breastfeeding women should not follow a strict ketogenic diet. Not recommended for individuals under 18. Always consult a healthcare provider before starting any restrictive diet.
Practical Tips
- Track net carbs (total carbs minus fiber), not total carbohydrates — fiber does not impact ketosis.
- Electrolytes are crucial during the first weeks: supplement sodium, potassium, and magnesium to avoid keto flu.
- Eat enough fat — going low-fat AND low-carb simultaneously can cause fatigue, muscle loss, and poor adherence.
Scientific Sources
- Mifflin MD et al. (1990) — A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 51(2):241-7. PMID 2305711
- Gibson AA et al. (2015) — Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Obes Rev. 16(1):64-76. PMID 25402637
- Volek JS & Phinney SD (2011) — The Art and Science of Low Carbohydrate Living. Beyond Obesity LLC. ISBN 978-0983490708
- Volek JS & Phinney SD (2012) — The Art and Science of Low Carbohydrate Performance. Beyond Obesity LLC. ISBN 978-0983490715
- Batch JT et al. (2020) — Advantages and Disadvantages of the Ketogenic Diet: A Review Article. Cureus. 12(8):e9639. PMID 32923239
- Bueno NB et al. (2013) — Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Br J Nutr. 110(7):1178-87. PMID 23651522
- Paoli A, Rubini A, Volek JS, Grimaldi KA. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. Eur J Clin Nutr. 2013;67(8):789–96. PMID 23801097
Frequently asked questions
- What is a ketogenic diet?
- A ketogenic (keto) diet is a high-fat, low-carbohydrate eating pattern that shifts your body into a metabolic state called ketosis. In ketosis, your body primarily burns fat for fuel instead of glucose from carbohydrates. Typically, 70-80% of calories come from fat, 15-25% from protein, and only 5-10% from carbohydrates (Volek & Phinney, 2011). This metabolic shift usually occurs within 2-7 days of restricting carbs below 20-50 grams per day.
- How many carbs can I eat on keto?
- Most people enter ketosis when consuming fewer than 20-50 grams of net carbohydrates per day. Net carbs are total carbs minus fiber. The standard keto diet (SKD) typically limits net carbs to about 20-25 grams daily. However, individual tolerance varies based on activity level, metabolic health, and body composition. Athletes and very active individuals may tolerate up to 50 grams while maintaining ketosis.
- What are the different types of keto?
- The three main types are: Standard Keto (SKD) with 75% fat, 20% protein, 5% carbs — the most researched and common approach. High-Protein Keto with 60% fat, 35% protein, 5% carbs — suitable for athletes or those wanting to preserve muscle mass. Modified Keto with 65% fat, 25% protein, 10% carbs — a more flexible approach that is easier to sustain long-term while still promoting ketosis.
- How long does keto adaptation take?
- The keto adaptation period typically lasts 2-4 weeks. During the first week, you may experience "keto flu" symptoms such as fatigue, headache, brain fog, and irritability as your body transitions from burning glucose to burning fat. These symptoms are largely due to electrolyte shifts and dehydration. After 2-4 weeks, most people report improved energy, mental clarity, and reduced hunger. Full fat-adaptation for athletic performance may take 6-12 weeks (Volek & Phinney, 2011).
- Why are electrolytes important on keto?
- On a ketogenic diet, your kidneys excrete more sodium due to lower insulin levels, which also leads to loss of potassium and magnesium. This electrolyte imbalance causes many "keto flu" symptoms. Phinney and Volek recommend 3,000-5,000 mg sodium, 3,000-4,700 mg potassium, and 300-500 mg magnesium daily during keto. Good sources include bone broth, leafy greens, avocados, nuts, and mineral-rich salt.
- Is keto safe long-term?
- Evidence on long-term safety is limited: a meta-analysis of trials lasting 12 months or more (Bueno et al., 2013) found slightly greater weight loss than with low-fat diets, but also higher LDL cholesterol. However, it is not recommended for people with type 1 diabetes, pancreatic disease, liver conditions, or kidney disease without medical supervision. Pregnant and breastfeeding women should avoid strict keto. Long-term adherence requires monitoring nutrient intake, including fiber, vitamins, and minerals. Consulting a healthcare provider before starting is strongly advised, especially for those on medication.
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