Keto Macro Calculator for Ketogenic Diet

How the Keto Calculator Works

This Keto Calculator estimates your daily calorie needs and ketogenic macronutrient targets based on your sex, age, height, weight, activity level, and weight goal. It uses the Mifflin-St Jeor equation — the same BMR formula as our BMR Calculator and Calorie Calculator — then applies an activity multiplier to find maintenance calories (TDEE). Your chosen weight goal adjusts that total before splitting calories into fat, carbs, and protein for a standard ketogenic diet.

Mifflin-St Jeor BMR

Basal metabolic rate (BMR) is the energy your body needs at rest. The calculator uses sex-specific formulas:

Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

BMR is multiplied by your activity level to estimate total daily energy expenditure (TDEE). For a broader energy overview, try the TDEE Calculator.

Activity Multipliers

Sedentary (little or no exercise): × 1.2
Light (exercise 1–2 days/week): × 1.4
Moderate (exercise 2–3 days/week): × 1.6
Active (exercise 4–5 days/week): × 1.75
Extra active (exercise 6–7 days/week): × 2.0
Professional athlete: × 2.3

Weight Goals and Minimum Calories

You can maintain weight or apply a daily calorie adjustment for mild, standard, or extreme weight loss or gain (−250, −500, −1000 or +250, +500, +1000 kcal). To protect against overly low intake, results are floored at 1,200 kcal/day for women and 1,800 kcal/day for men.

Default Ketogenic Macro Split

The standard ketogenic ratio is 70% fat, 5% carbohydrates, and 25% protein. You can override these percentages with custom macros; they must total 100%. Grams are calculated using 9 kcal per gram of fat and 4 kcal per gram of carbs and protein. Pair this tool with the Protein Calculator and Fat Intake Calculator for additional macronutrient guidance.

Frequently Asked Questions

What is a ketogenic diet?

A ketogenic diet is very low in carbohydrates and high in fat. By sharply limiting carbs, your body shifts toward burning fat and producing ketones for energy. Typical keto macros are about 70% fat, 5% carbs, and 25% protein, though individual needs vary.

How many carbs should I eat on keto?

On a standard ketogenic diet, carbohydrates usually make up about 5% of daily calories — often roughly 20–40 grams per day depending on your total calorie target. This calculator shows your specific carb grams based on your personalized calorie and macro split.

Why is there a minimum calorie limit?

Very low calorie intake can cause nutrient deficiencies, muscle loss, and hormonal disruption. Health guidelines commonly recommend not going below 1,200 kcal/day for women or 1,800 kcal/day for men without medical supervision. The calculator enforces these floors when a large deficit would otherwise apply.

Can I use custom macro percentages?

Yes. Enable custom macros to set your own fat, carb, and protein percentages. Some people use slightly higher fat (75%) and lower protein (20%) on keto. Your three percentages must add up to exactly 100% for the calculator to produce results.

Is the keto diet safe for everyone?

Not necessarily. People with diabetes, kidney disease, liver conditions, or who are pregnant or breastfeeding should consult a doctor before starting keto. This calculator provides estimates only and does not replace personalized medical or dietitian advice.

How accurate is this calculator?

It uses widely accepted formulas for BMR and standard activity multipliers, but individual metabolism, body composition, and health status all affect real needs. Treat the output as a starting point and adjust based on progress, energy levels, and professional guidance.

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Keto Calculator