This keto macro calculator estimates your daily calories, then splits them into net carbs, protein and fat. It uses the Mifflin-St Jeor equation for resting energy, a standard activity multiplier, and the carb and protein levels you choose. Results are estimates to start from, not medical advice.
Key Takeaways
- Calories come first: the Mifflin-St Jeor equation estimates resting energy from sex, age, height and weight.
- Net carbs are set low on purpose, usually 20 to 50 grams a day on a ketogenic diet.
- Protein is set per kilogram of body weight; 1.4 to 2.0 g/kg is the range the International Society of Sports Nutrition gives for people who exercise.
- Fat fills the remaining calories, which is why it ends up as the largest share on keto.
Calculate Your Keto Macros
How Does the Keto Macro Calculator Work?
The calculator works in four steps: resting energy, daily calories, then carbs and protein, with fat filling the rest.
- Resting energy (BMR) uses the Mifflin-St Jeor equation (1990): 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 for men or −161 for women.
- Daily calories multiply BMR by an activity factor from 1.2 (sedentary) to 1.9 (extra active), then apply your goal: −20% or −10% to lose weight, +10% to gain.
- Net carbs and protein are the levels you pick. Each gram of carbohydrate or protein counts as 4 calories.
- Fat is what remains, at 9 calories per gram.
How Much Protein Do You Need on Keto?
Protein needs depend mostly on body weight and activity. The International Society of Sports Nutrition position stand (2017) gives 1.4 to 2.0 g per kg of body weight a day for people who exercise, which is why the calculator offers 1.2, 1.6 and 2.0 g/kg. People with kidney disease should ask their doctor before raising protein.
How Many Net Carbs Should You Eat?
Most ketogenic plans keep carbohydrate under about 50 grams a day, and strict plans use about 20 grams of net carbs (StatPearls, NCBI Bookshelf). Check what foods fit with the keto net carbs chart.
Related guides: Guide to Keto Diet: Rules, Macros, and Sample Menu, Why Am I Not Losing Weight on Keto Diet? Hidden Mistakes Explained, How to Lose Weight on Keto Diet: 11 Proven Strategies, The Ultimate Beginner’s Guide to the Keto Diet: Everything You Need to Know to Get Started.
Frequently Asked Questions
How are keto macros calculated?
Keto macros are calculated by estimating daily calories, setting net carbs low (usually 20 to 50 g), setting protein by body weight, and giving the remaining calories to fat.
Is this keto calculator accurate?
It gives an estimate. The Mifflin-St Jeor equation predicts resting energy for groups of people, but an individual can differ, so adjust calories after two to four weeks based on your weight trend.
Who should not use a keto calculator without medical advice?
People who are pregnant or breastfeeding, under 18, take medication for diabetes or blood pressure, or have kidney, liver or pancreatic disease should talk to a doctor before starting a ketogenic diet.
Last reviewed October 2026.
This article is for informational purposes only and is not medical advice. Talk to your doctor or a registered dietitian before changing your diet, especially if you have a medical condition or take medication. Read our medical disclaimer and editorial policy.