Keto Calculator

Macros — short for macronutrients — are fat, protein, and carbohydrates, the three main sources of calories in your diet. On a ketogenic diet, tracking macros is essential because the diet works by keeping carbs very low (typically under 25–30g net per day) so your body enters ketosis and burns fat for fuel instead of glucose. Getting the right balance ensures you stay in ketosis and meet your energy needs.

The calculator first estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula, then multiplies it by your activity level to get your Total Daily Energy Expenditure (TDEE). A calorie adjustment (deficit or surplus) is applied based on your goal. Protein is set using your lean body mass, carbs are fixed to your chosen net carb limit, and the remaining calories are filled by fat.

Body fat percentage is used to calculate your lean body mass (LBM), which is your total weight minus fat mass. Protein targets on keto are based on lean body mass rather than total weight, because muscle tissue needs protein support — excess body fat does not. A more accurate body fat estimate leads to more precise macro recommendations.

A moderate deficit of around 20% below your TDEE is a common starting point — it's aggressive enough to produce noticeable fat loss (roughly 0.5–1 lb per week) while still providing enough calories to preserve muscle and sustain energy. Very large deficits can lead to muscle loss and metabolic adaptation, so most people do best staying between a 10–25% deficit.

A typical ketogenic macro split is roughly 70–75% of calories from fat, 20–25% from protein, and 5% or less from carbohydrates. However, the exact grams vary significantly by individual based on body size, activity level, and goals. This calculator personalizes those targets specifically for you rather than applying a one-size-fits-all percentage.

Net carbs are total carbohydrates minus fiber (and sometimes sugar alcohols). Fiber is not digested and does not raise blood sugar or impact ketosis, so most keto practitioners track net carbs. The standard keto target is 20–25g net carbs per day to reliably maintain ketosis for most people.

Excess protein can theoretically be converted to glucose through a process called gluconeogenesis, but research shows this process is demand-driven — your body only converts as much protein as needed. Eating moderate to high protein on keto is generally fine and helps preserve muscle mass, especially during a calorie deficit. The risk of being 'kicked out' of ketosis from protein is often overstated.

The calculator uses well-validated formulas (Mifflin-St Jeor for BMR and Katch-McArdle when body fat is provided) that are accurate for most people within a reasonable margin. Individual factors like metabolic health, hormones, and gut microbiome can cause variation. Use the results as a starting point, track your progress for 2–3 weeks, and adjust calories or macros if needed based on real-world results.