Keto Macro Calculator
Enter your details and get keto macros matched to your goal: carbs capped at 30 grams to keep you in ketosis, protein set to protect muscle, and fat filling the rest. Built by a physiotherapist, with the formula shown and the electrolyte guidance most keto calculators skip.
Your results
Keto split from the Mifflin-St Jeor equation: carbs capped at 30 g, protein at 1.6 g per kg, fat filling the rest.
Your daily macro split
| Per meal (4 meals/day) | Target |
|---|---|
| Proteinthe anchor of every meal | |
| Carbohydratesmostly around training | |
| Fatspread through the day |
⚠ This target is very low. Dropping below roughly 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision risks muscle loss and slower healing. Pick maintenance or talk to us first.
How this keto macro calculator works
Most keto calculators hand you three numbers, no explanation. This one shows its work: a target you cannot check is a target you should not trust. The calculation runs in four steps, all on this page:
Carbs are capped first
Thirty grams a day keeps most people in ketosis. Count total carbs, fiber included.
Protein stays moderate
At 1.6 g per kg, protein protects muscle without excess. More is not better on keto; the carb cap is doing the work.
Fat fills the rest
Whatever calories remain become fat: your main fuel now. When the scale stalls, trim fat portions, never the carb cap.
What ketosis actually is
Ketosis is a metabolic state, not a miracle. When carbohydrate intake stays very low for a few days, the liver runs short of glucose and starts converting fat into ketone bodies, which your brain and muscles burn instead. That is the whole mechanism: low carbs in, ketones out. Appetite usually drops, which is why keto works for fat loss: same calorie deficit as any other diet.
Getting there takes two to four days under your carb cap. A single high-carb meal can pause ketone production for a day or more, which is why the 30-gram cap matters more than any other number on this page.
How to tell you are in ketosis
You do not need gadgets. The usual signs: hunger fades, afternoon energy steadies instead of crashing, and some notice a fruity or metallic taste in the mouth for the first week or two. Ketone urine strips are cheap and confirm it, though they get less reliable once the body adapts.
Electrolytes: the part most keto guides skip
Here is the physiology no calculator can do for you. When insulin drops in the first week of keto, the kidneys release sodium and water with it, and potassium and magnesium follow. The result is the headache, fatigue and leg cramps of keto flu, and it is almost entirely preventable.
Aim for 3 to 5 grams of sodium a day in the first two weeks: salt food generously, drink broth, or add a quarter teaspoon of salt to water twice a day. Get potassium from leafy greens, avocados and salmon. Take 300 to 400 mg of magnesium in the evening for sleep and cramps, and drink water steadily rather than in floods.
From the physio’s desk: muscle cramps are one of the most common complaints I hear from people starting keto, and they are almost always an electrolyte problem, not a fitness problem. If your calves seize at night in week one, reach for salt water before you reach for worry.
Who should not do keto
Keto is a poor choice for some people, and this matters more than any macro number. Do not start keto if you are pregnant or breastfeeding, if you have kidney disease or a history of kidney stones, if you take diabetes medication such as insulin, or if you have a history of eating disorders. Endurance athletes and heavy lifters should know performance often dips for weeks during adaptation. When in doubt, ask your clinician first. A calculator cannot screen you; a doctor can.
Keto and injury recovery: go easy
Two cautions from the clinic. First, do not stack a hard deficit on top of an injury. Healing is metabolically expensive, and keto already suppresses appetite, which makes accidental under-eating easy. While you are hurt, run this calculator at maintenance, not fat loss.
Second, watch electrolytes even more closely when you cannot train. Less sweating shifts your sodium needs, and cramping in an immobilized limb is miserable. Keep protein at its full 1.6 g per kg, keep the carb cap, and let fat carry the calories. If dizziness, persistent fatigue or stalled healing show up, the diet is the first suspect. Fix the fuel before you blame the rehab.
Keto macro splits by goal
Here is what the calculator produces for a 75 kg adult at each goal:
| Goal | Calories | Protein / Carbs / Fat |
|---|---|---|
| Fat lossTDEE minus 500 kcal | 2,000 | 120 g / 30 g / 156 g |
| Maintenanceeat at TDEE | 2,500 | 120 g / 30 g / 211 g |
| Muscle gainTDEE plus 250 kcal | 2,750 | 120 g / 30 g / 239 g |
Notice what does not move: protein and carbs are fixed on keto. Fat is the only dial that turns with the goal, because fat is the fuel. The per-meal table matters here: 30 grams across four meals is under 8 grams a meal, so vegetables and careful portions, not guesswork.
Note: total carbs here; fiber is not subtracted. Counting total carbs is the conservative approach that keeps the most people in ketosis.
Macro calculators for specific goals
One formula, different targets. Each calculator below runs the same validated method as this page, tuned to one goal:
Macro Calculator
The standard protein-first split with higher carbs: same trusted math, for fat loss, maintenance or muscle gain.
Macro Calculator for Weight Loss
Higher protein and a steady deficit, built to cut fat while keeping the muscle that protects your joints.
Macro Calculator for Muscle Gain
A lean surplus with protein set for growth, so the weight you add is muscle, not just mass.
Macro Calculator for Women
Protein targets that account for the realities of women’s physiology: muscle preservation, bone health and training through hormonal cycles.
Want your maintenance calories first? Start with our TDEE calculator, then come back here to split them into keto macros.
Keto macro calculator: frequently asked questions
How many carbs can I eat and stay in ketosis?
Most people stay in ketosis at or under 30 to 50 grams of total carbs per day. This calculator caps carbs at 30 grams, which keeps the large majority in ketosis without any testing. Very active or larger people sometimes tolerate up to 50 grams. If you want certainty rather than probability, test your ketones after two weeks of strict adherence.
Will eating protein kick me out of ketosis?
Not at normal amounts. The fear comes from gluconeogenesis, the process that converts protein to glucose, but it is demand-driven: your body does not turn extra protein into glucose just because it is available. At 1.6 grams per kilogram, protein protects your muscle and ketosis continues.
What is keto flu and how do I avoid it?
Keto flu is the headache, fatigue and muscle cramps of the first week, caused mostly by sodium and water loss as insulin drops. Prevent it with 3 to 5 grams of sodium daily (salt food generously or drink broth), potassium from leafy greens and avocados, 300 to 400 mg of magnesium in the evening, and steady water intake. Most people feel normal within a week.
Is keto safe long term?
For healthy adults it can be sustained, but it removes whole food groups, so plan for fiber, micronutrients and regular blood work. It is not advised during pregnancy, with kidney disease, or with a history of eating disorders. An annual check-in with your clinician is sensible.
Can I build muscle on keto?
Yes, though usually more slowly than with carbohydrates in the picture. Keep protein at 1.6 grams per kilogram, use the small surplus this calculator gives for muscle gain, and train progressively. Explosive sessions often feel flat without glycogen in the first months; that is the trade, not a flaw in your training.
Do I still need a calorie deficit on keto?
For fat loss, yes. Ketosis quiets hunger, which makes eating less easier, but the deficit still does the work. This calculator applies the same steady 500 kcal deficit for fat loss as any other approach. Anyone promising fat loss without an energy deficit is selling something.
PhysioUBK Health Tools · Estimates only, not medical advice · physioubk.com