Introduction
The Keto Calculator helps you figure out exactly how much fat, protein, and carbs you should eat each day on a ketogenic diet. A keto diet is a way of eating where you cut way back on carbs and eat more fat instead. This pushes your body into a state called ketosis, where it burns fat for energy rather than sugar. Getting your numbers right matters a lot because eating too many carbs can kick you out of ketosis, and eating too much or too little protein can slow your progress. This tool takes your personal details — like your age, weight, height, and activity level — and gives you a clear daily breakdown of macros tailored to your goals, whether you want to lose weight, maintain, or gain muscle. For a broader look at macronutrient planning beyond keto, you can also try our Macro Calculator.
How to Use Our Keto Calculator
Enter your body details and activity level below to find out how many grams of fat, protein, and carbs you should eat each day on a keto diet.
Gender: Select whether you are male or female. This matters because men and women burn calories at different rates.
Age: Enter your age in years. Your body needs different amounts of energy as you get older.
Weight: Enter your current weight in pounds or kilograms. This helps figure out how many calories your body uses each day. If you're curious about what your optimal weight might be, check out our Ideal Body Weight Calculator.
Height: Enter your height in feet and inches or centimeters. Along with your weight, this is used to calculate your base metabolic rate.
Activity Level: Pick the option that best matches how active you are during the week. Someone who sits most of the day will need fewer calories than someone who exercises often.
Body Fat Percentage (if known): Enter your estimated body fat percentage if you know it. This helps the calculator give you a more accurate protein target to protect your lean muscle mass. You can use our Lean Body Weight Calculator to better understand your body composition.
Net Carb Intake: Choose how many grams of net carbs you want to eat per day. Most people on keto stay between 20 and 50 grams. A lower number helps your body get into ketosis faster. For more detail on daily carbohydrate planning, see our Carb Calculator.
Calorie Goal: Select whether you want to lose weight, maintain weight, or gain weight. If you pick weight loss, you can also set how big of a calorie deficit you want, such as 10%, 15%, or 20% below your maintenance calories.
What Is a Keto Calculator?
A keto calculator is a tool that figures out exactly how many grams of fat, protein, and net carbs you should eat each day while following a ketogenic diet. The ketogenic (keto) diet is a high-fat, moderate-protein, very low-carb eating plan designed to shift your body into a metabolic state called ketosis. In ketosis, your body burns fat for fuel instead of carbohydrates, which can lead to weight loss, steadier energy levels, and reduced hunger.
How the Keto Diet Works
Normally, your body runs on glucose, which comes from carbohydrates like bread, rice, and sugar. When you eat very few carbs — typically under 20 to 50 grams of net carbs per day — your body runs out of its preferred fuel source. It then starts breaking down stored fat into molecules called ketones, which your brain and muscles can use for energy. This process is what makes the keto diet effective for fat loss.
The standard keto macro ratio is roughly 70% of calories from fat, 25% from protein, and 5% from net carbs. These percentages can be adjusted based on your goals and activity level, but keeping carbs very low is the key to staying in ketosis.
Key Terms You Should Know
- BMR (Basal Metabolic Rate): The number of calories your body burns at rest just to keep you alive — things like breathing, pumping blood, and maintaining body temperature. This calculator uses the Mifflin-St Jeor formula by default, or the Katch-McArdle formula if you provide your body fat percentage.
- TDEE (Total Daily Energy Expenditure): Your BMR multiplied by an activity factor. This is the total number of calories you burn in a full day, including exercise and daily movement. Your macro targets are based on this number.
- Net Carbs: Total carbohydrates minus fiber. Net carbs are what matter on keto because fiber does not raise blood sugar or interfere with ketosis. Our Fiber Calculator can help you make sure you're still getting enough daily fiber.
- Macros (Macronutrients): The three main nutrients your body needs in large amounts — fat, protein, and carbohydrates. Each one provides a specific number of calories per gram: fat has 9 calories per gram, while protein and carbs each have 4 calories per gram. For help dialing in your protein intake specifically, try our Protein Calculator.
Why Body Fat Percentage Matters
If you enter your body fat percentage, the calculator switches to the Katch-McArdle formula, which estimates your BMR based on lean body mass rather than just your total weight. This tends to give more accurate results, especially for people who are very muscular or carry a higher amount of body fat. Tools like the Waist to Hip Ratio Calculator can also give you useful insight into your body composition. If you are unsure of your body fat percentage, you can use the visual silhouette estimator included in the calculator or simply leave the field blank.
Choosing Your Goal
Your calorie target depends on what you are trying to achieve. If your goal is to lose weight, the calculator subtracts a percentage from your TDEE to create a calorie deficit. A 20% deficit is a common and sustainable starting point. If your goal is to gain muscle, it adds a calorie surplus instead. For maintenance, your target calories simply match your TDEE.
Tips for Success on Keto
- Stay hydrated. When you cut carbs, your body holds less water, so you need to drink more fluids and replenish electrolytes like sodium, potassium, and magnesium. Our Water Intake Calculator can help you determine how much you should be drinking each day.
- Focus on whole foods. Build your meals around fatty fish, eggs, avocados, nuts, olive oil, meat, leafy greens, and non-starchy vegetables.
- Track your macros closely for at least the first few weeks. It is easy to underestimate carbs or overeat protein, both of which can slow your results.
- Be patient with the adjustment period. Many people experience temporary symptoms like fatigue, headaches, or irritability during the first week. This is often called the "keto flu" and usually passes within a few days. Getting enough quality sleep can also help your body adapt more smoothly.
- Protein matters. Eating enough protein protects your muscle mass while you lose fat. The calculator's default of 25% protein is a solid starting point for most people. If you're also strength training, our 1RM Calculator can help you plan your workouts alongside your nutrition.
- Watch your caffeine. Many keto dieters rely on coffee and tea. Use our Caffeine Calculator to make sure you're not overdoing it.
Use the results from this calculator as a daily guide. Weigh and measure your food when possible, check in with your progress every few weeks, and adjust your calorie deficit or surplus as your weight changes. Tracking metrics like your VO2 max or heart rate zones can also help you monitor fitness improvements alongside your dietary changes. If you have any medical conditions or take medications, talk to your doctor before starting a keto diet.