The ketogenic diet flips your body’s fuel source from carbohydrates to fat. To reach and stay in ketosis, your macros must be precise: very low carbs, moderate protein, and high fat. Guess the numbers and you may never get into ketosis at all. This macro calculator keto tool takes the guesswork out: enter your stats once and get your personal fat, protein, and carb targets in seconds.
Enter your details below, then select the “Keto” preset tab inside the calculator. It applies the classic ketogenic split (about 75% fat, 20% protein, 5% carbs) and computes your exact daily gram targets. Pair it with the “Lose weight (cut)” goal if fat loss is your aim.
How the math works
Step 1 – BMR (Mifflin-St Jeor, 1990): Men: 10 x weight(kg) + 6.25 x height(cm) – 5 x age + 5. Women: same, but – 161 instead of + 5. BMR is what you burn at complete rest.
Step 2 – TDEE: BMR multiplied by your activity factor (1.2 sedentary up to 1.9 extremely active) gives total daily energy expenditure.
Step 3 – Goal adjustment: a 500 kcal daily deficit for fat loss, maintenance for staying the same, or a 300-500 kcal surplus for muscle gain.
Step 4 – Macro split: the preset percentages are applied to your calorie target. Protein and carbs count 4 kcal per gram, fat counts 9 kcal per gram.
What Are the Keto Macro Percentages?
The standard ketogenic split is 70-75% of calories from fat, 20-25% from protein, and 5-10% from carbs. For most people that means staying under 30-50 grams of net carbs per day. Protein stays moderate: too little costs you muscle, and there is no need to fear it — the “too much protein kicks you out of ketosis” worry is overstated for most people.
How Many Carbs Can I Eat on Keto?
Most people enter ketosis under 50 grams of net carbs daily; aiming for 20-30 grams is the safest zone. Net carbs means total carbs minus fiber, so fibrous vegetables are your friend. Track net carbs, not total carbs, and be strictest in the first 2-3 weeks.
Do I Still Need a Calorie Deficit on Keto?
Yes. Keto suppresses hunger for many people, which makes eating less feel effortless — but fat loss still requires burning more than you eat. Set the calculator’s goal to “Lose weight (cut)” and it builds the deficit into your keto macros automatically.
Frequently Asked Questions
How long does it take to enter ketosis?
Usually 2-4 days of staying under 50 grams of net carbs. Signs include reduced hunger, stable energy, and sometimes a metallic taste or fruity-smelling breath in the first week.
Can I eat too much protein on keto?
For most people, no. Keep protein around 1.6-2.0 grams per kilogram of bodyweight to protect muscle. Only truly extreme intakes might nudge sensitive individuals out of deep ketosis.
What is the keto flu?
Headache, fatigue, and irritability in the first week, caused mostly by shedding water and electrolytes as your carb stores empty. More salt, plenty of water, and magnesium fix it — it passes within days.
Will keto work without exercise?
Diet drives fat loss; exercise drives body composition. You can lose weight on keto without training, but adding 2-4 strength sessions per week preserves muscle and shapes the result.