How many carbs can I eat on keto?

Most people need to stay under 20-30 g of net carbs a day to reach and maintain ketosis. Some active individuals maintain it up to 50 g, but 20 g is the reliable starting point.

Total carbohydrate minus fibre, and in most countries minus sugar alcohols like erythritol. Fibre is not digested into glucose, so it does not count against your ketogenic limit.

How much protein should I eat on keto?

1.2-2.0 g per kilogram of body weight. Going higher will not typically break ketosis, despite the common claim - and under-eating protein during weight loss reliably costs you muscle.

How long does it take to get into ketosis?

Two to four days of eating under 20-30 g of net carbs for most people, occasionally up to a week. Fatigue and headaches during that window are the keto flu, and they respond well to extra salt and fluids.

Will I lose weight faster on keto?

Initially yes, but the first several pounds are water released alongside depleted glycogen. Beyond that, fat loss tracks your calorie deficit like any other diet.

Keto Calculator

Get your ketogenic macros - net carbs, protein and fat - based on your body, activity level and goal.

Enter your details and your result will appear here.

What Is Keto?

This keto calculator sets your daily ketogenic macros: how many net carbs to stay under, how much protein to eat, and how much fat fills the rest of your calories.

A ketogenic diet works by keeping carbohydrate low enough that the body shifts to producing ketones from fat for fuel. Getting there is mostly about one number - the carb ceiling - with protein and fat arranged around it.

Understanding Your Keto Result

The defining constraint is carbohydrate. Most people enter nutritional ketosis below 20-30 g of net carbs a day, which is a genuinely restrictive limit - a single banana would use most of it.

Protein sits in a moderate band, typically 1.2-2.0 g per kilogram of body weight. High enough to preserve muscle, but not so high that gluconeogenesis becomes an issue for the small number of people who are sensitive to it. In practice, worries about protein knocking people out of ketosis are overstated.

Fat then fills the remaining calories. On a fat-loss protocol, your own body fat contributes part of that energy, which is why keto meal plans for weight loss look lower in dietary fat than maintenance ones.

How Is Keto Calculated?

Calories = TDEE adjusted for goal
Net carbs: fixed allowance, typically 20-30 g/day
Protein: 1.2-2.0 g per kg body weight
Fat: remaining calories / 9

How to use this keto calculator

Enter your sex, age, height, weight, activity level and goal. You will get daily targets for net carbs, protein and fat, along with the calorie total they add up to.

Track net carbs closely for the first month. Protein and fat can be approximate; the carb ceiling cannot, because it is the thing that determines whether the diet is ketogenic at all.

Hitting your macros in practice

Build meals around a protein source, add a low-carb vegetable, then add fat to close the gap - olive oil, butter, avocado, cheese or nuts. Hidden carbohydrate in sauces, dressings and processed foods is what derails most beginners.

Salt matters more than on any other diet. Ketosis increases sodium excretion, and most keto flu symptoms are electrolyte problems wearing a costume.

Adjusting over time

Recalculate after every 10-15 lb of weight loss, since your calorie needs drop as you get smaller. If fat loss stalls for three weeks, reduce dietary fat rather than protein - fat is the flexible macro here.

Some people add carbohydrate back around training once fat-adapted. That moves you toward a low-carb rather than strictly ketogenic diet, which is a perfectly reasonable place to end up.

Methodology

Total calories come from the Mifflin-St Jeor BMR multiplied by your activity factor, then adjusted for your goal. Net carbs are set as a fixed daily allowance rather than a percentage, protein is scaled to body weight, and fat takes the remaining energy at 9 calories per gram.

Worked Example

A 35-year-old woman, 5 ft 6 in and 170 lb (77 kg), lightly active, has a maintenance level near 2,000 calories. Targeting fat loss at 1,600 calories, her keto macros come out around 20 g net carbs, 116 g protein and 116 g fat.

That is roughly 5% of calories from carbohydrate, 29% from protein and 66% from fat - the macro profile people recognise as keto, arrived at from her body rather than from a generic ratio.

Important Limitations

Ketogenic diets are not superior to other diets for fat loss once calories and protein are matched; the advantage most people experience is appetite suppression and simplicity. The first one to two weeks commonly bring fatigue, headaches and cramps as sodium, potassium and magnesium are lost with water. Endurance athletes often see reduced high-intensity performance. Anyone with type 1 diabetes, on SGLT2 inhibitors, with pancreatic or liver disease, or who is pregnant should not start keto without medical supervision.

Frequently Asked Questions

How many carbs can I eat on keto?: Most people need to stay under 20-30 g of net carbs a day to reach and maintain ketosis. Some active individuals maintain it up to 50 g, but 20 g is the reliable starting point.
What are net carbs?: Total carbohydrate minus fibre, and in most countries minus sugar alcohols like erythritol. Fibre is not digested into glucose, so it does not count against your ketogenic limit.
How much protein should I eat on keto?: 1.2-2.0 g per kilogram of body weight. Going higher will not typically break ketosis, despite the common claim - and under-eating protein during weight loss reliably costs you muscle.
How long does it take to get into ketosis?: Two to four days of eating under 20-30 g of net carbs for most people, occasionally up to a week. Fatigue and headaches during that window are the keto flu, and they respond well to extra salt and fluids.
Will I lose weight faster on keto?: Initially yes, but the first several pounds are water released alongside depleted glycogen. Beyond that, fat loss tracks your calorie deficit like any other diet.