Keto Macro Calculator,
net carbs, protein & fat targets.

Keto guide

Net carbs, ketosis, and why fat is your primary fuel.

What is a ketogenic diet?

A ketogenic diet is a very low-carbohydrate, high-fat eating pattern that shifts the body's primary fuel source from glucose to ketone bodies. When carbohydrate intake drops below roughly 50 g per day (and often below 25 g for reliable ketosis), liver glycogen is depleted within 24–48 hours. The liver then converts stored fat and dietary fat into ketones — beta-hydroxybutyrate (BHB), acetoacetate, and acetone — which cross the blood-brain barrier and power most tissues.

The state of nutritional ketosis is defined by blood BHB levels above 0.5 mmol/L. Most people achieve and maintain this reliably by keepingnet carbohydrates at or below 25 g per day, which is the value this calculator uses as its strict cap.

What are net carbs?

Net carbs = Total carbohydrates − Dietary fibre

Dietary fibre is a carbohydrate, but it passes through the digestive tract largely unabsorbed and does not raise blood glucose. When calculating your carbohydrate impact on ketosis, you subtract fibre from the total carb count on the nutrition label to get the net carb figure. In the United States, fibre is already listed separately on nutrition panels; in Europe and Australia, carbohydrates are sometimes listed "of which sugars" and total carbs already exclude fibre — read the label carefully.

Sugar alcohols (erythritol, xylitol, sorbitol) are treated differently. Erythritol is generally subtracted in full like fibre because it is almost entirely excreted. Other sugar alcohols have a partial glycaemic impact (typically half their gram weight) and should only be partially subtracted. This calculator tracks net carbs only — adjust your food choices to stay under the 25 g target.

Why protein must stay moderate on keto

One of the most common keto mistakes is over-consuming protein. When protein intake is very high, excess amino acids undergo gluconeogenesis— the liver converts them to glucose. This can raise blood sugar, spike insulin, and suppress ketone production, kicking you out of ketosis even if your carb intake is perfect.

The standard recommendation is 0.8 g of protein per pound(approximately 1.76 g per kg) of total body weight for most adults. This is enough to preserve lean muscle mass during fat loss — the primary goal of ketogenic dieting for most people — without triggering significant gluconeogenesis. Athletes and individuals actively building muscle may increase this modestly to 1.0 g/lb, but the high-fat context of keto makes extreme protein intake counterproductive.

How fat fills the keto budget

Once carbs and protein are set, fat fills the remainder of your calorie target. On a standard ketogenic split this is typically 65–75% of total calories from fat — far higher than any other mainstream dietary pattern. This is intentional: dietary fat triggers minimal insulin response, keeps you satiated, and directly provides the substrate for ketone synthesis.

Common keto-friendly fat sources include: avocado and avocado oil, olive oil, coconut oil, butter and ghee, fatty fish (salmon, mackerel, sardines), full-fat dairy, nuts (macadamia, pecans), and the fat marbling in beef. Limit polyunsaturated vegetable oils (corn, soybean) due to their high omega-6 content.

TDEE and caloric goals on keto

Ketosis is a metabolic state achieved by restricting carbs — it is not inherently weight-loss magic. Calories still matter. This calculator first computes your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation (the gold standard per the Academy of Nutrition and Dietetics), then applies a goal modifier:

• Lose weight: 20% caloric deficit. Creates roughly 0.4–0.5 kg fat loss per week for most people. Keto's natural appetite suppression makes adherence to a deficit easier than many other diets.
• Maintain: TDEE calories with full keto macro split. Ideal for body recomposition, therapeutic ketosis, or metabolic health without the goal of weight change.
• Build muscle: 10% caloric surplus. A modest surplus limits fat gain while providing enough calories for hypertrophy. Muscle building on keto is slower but well-documented, particularly after a 4–6 week adaptation phase.