Keto Macro Calculator
Set ketogenic macros: carbs capped, protein from lean mass, fat filling the rest.
Your details
Light exercise 1–3 days a week
A ketogenic diet interacts with medication: particularly insulin, sulfonylureas and blood-pressure drugs, where doses often need lowering within days. Do not start one on medication without talking to the prescriber first.
This sets ketogenic macros from your calorie target: high fat, moderate protein, and carbohydrate low enough to reach ketosis.
It gives grams for each, and flags where the standard percentages conflict with a sensible protein floor.
How a ketogenic diet is set up
A ketogenic diet restricts carbohydrate far enough that the body shifts to running on ketones, made from fat, instead of glucose. The usual threshold is under 20-50 g of carbohydrate a day.
The typical split is roughly 70-75% fat, 20-25% protein, 5-10% carbohydrate. On 2,000 calories that is about 167 g fat, 100 g protein and 25 g carbohydrate.
Two things worth being clear about. The rapid first-week weight loss is water, not fat: glycogen binds several grams of water per gram, and depleting it drops 2-5 lb that returns when you eat carbohydrate again. And ketosis is not required for fat loss — a calorie deficit is. Keto works for people it works for because it controls appetite well, not because ketones burn fat by themselves.
Note the protein figure. A 70 kg person needs about 112 g at 1.6 g/kg, so the standard 20% can sit below the floor that protects muscle.
What to enter
- Calorie target
- From your TDEE adjusted for your goal. Keto does not exempt you from needing a deficit.
- Carbohydrate limit
- 20 g of net carbs is strict and reliable; 50 g works for many people. Individual tolerance varies.
- Protein target
- Set this from body weight, not as a percentage. 1.6-2.2 g/kg protects muscle.
- Fat
- Takes the remainder. On keto it is the energy source rather than something to minimise.
Terms worth knowing
- Net carbs
- Total carbohydrate minus fibre and sugar alcohols. Most keto tracking uses net rather than total.
- Keto flu
- Headache, fatigue and irritability in the first week, largely from electrolyte loss as glycogen and its water leave.
- Nutritional ketosis
- Blood ketones roughly 0.5-3.0 mmol/L. Distinct from diabetic ketoacidosis, which is a medical emergency.
- Protein and ketosis
- The old worry that protein prevents ketosis is largely overstated. Adequate protein is more important than staying deeply in ketosis.
What this assumes
Fat loss requires a calorie deficit. A ketogenic diet can create one through appetite control, and it does not create one automatically.
This is general information. Type 1 diabetes, kidney disease, pancreatitis and some medications make keto unsuitable or require medical supervision.
How to calculate your keto macros
Set carbohydrate as a hard cap, protein from body weight, and give fat the rest.
- carbs
- Net carbohydrate, a cap rather than a target
- protein
- From body weight, not from a percentage
- fat
- The remaining calories, at 9 per gram
Set the carbohydrate cap. 20 g of net carbs reaches ketosis reliably. Some people maintain it at 50 g, which is much easier to live with.
Set protein from body weight. 1.6-2.2 g/kg. At 70 kg that is 112-154 g, which is often more than a 20% rule would give.
Give the remaining calories to fat. 2,000 − 100 (carbs) − 448 (112 g protein) = 1,452 calories, which is 161 g of fat.
Manage electrolytes from day one. Sodium, potassium and magnesium all deplete as glycogen water leaves. Most of "keto flu" is this, and it is largely preventable.
See a worked example: where the standard percentages break
- Calories
- 2,000
- Body weight
- 70 kg
Standard 75/20/5: 167 g fat, 100 g protein, 25 g carbs.
But a 70 kg person needs 112 g of protein at 1.6 g/kg, and 100 g is below that.
Setting protein properly: 112 g protein (448 cal), 25 g carbs (100 cal), leaving 1,452 for 161 g of fat.
The percentages become 73/22/5, which is still comfortably ketogenic. Nothing was lost by protecting the protein.
161 g fat, 112 g protein, 25 g carbs
Frequently asked questions
Under 20-50 g of net carbs a day. Twenty is strict and reaches ketosis reliably; fifty works for many people and is much easier to sustain.
Individual tolerance varies with activity level and metabolic health. Active people can often eat more carbohydrate and stay in ketosis.
Water. Each gram of stored glycogen binds several grams of water, and depleting glycogen releases all of it.
It is not fat, and it returns as soon as you eat carbohydrate again. Real fat loss follows the same rate as any other diet with the same deficit.
Not inherently. Controlled trials that match calories and protein find similar fat loss between ketogenic and non-ketogenic diets.
Where it genuinely helps is appetite. Many people eat less on keto without trying, and a diet you naturally adhere to beats a theoretically better one you abandon.
Headache, fatigue, irritability and muscle cramps in the first week, mostly caused by electrolyte loss as glycogen water is excreted.
It is largely preventable: increase sodium deliberately (broth or salted food), and keep potassium and magnesium up. Most people who "cannot tolerate keto" are experiencing an electrolyte problem rather than a metabolic one.
This concern is largely overstated. Gluconeogenesis is demand-driven rather than supply-driven, so eating adequate protein does not flood you with glucose.
Protein is more important than depth of ketosis. Cutting protein to stay deeply in ketosis costs muscle for no real benefit.
Evidence for very long-term adherence is limited, and short and medium-term trials have generally been reassuring for healthy adults.
Some conditions make it unsuitable: type 1 diabetes, pancreatitis, gallbladder disease and some kidney conditions. Anyone on diabetes or blood pressure medication should involve a doctor, because both may need adjusting quickly.
Problems people actually run into
Setting protein as a percentage
The standard 20% gives 100 g on a 2,000-calorie diet, which is below what a 70 kg person needs to protect muscle in a deficit.
Set protein in grams from body weight and let fat take the remainder. The result is still comfortably ketogenic and considerably better for body composition.
Assuming ketosis does the work
Being in ketosis does not create a calorie deficit. Fat is energy-dense at 9 calories per gram, and it is entirely possible to eat at maintenance or above on keto.
Track calories at least at the start. The appetite suppression is real and it is not a guarantee.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Last updated: September 4, 2026