Keto Calculator — Ketogenic Diet Macros

Formula

How this is calculated

The calculator first estimates your Basal Metabolic Rate (BMR) — the calories your body burns at rest — using the 1990 Mifflin-St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women. BMR is multiplied by a standard activity factor to get Total Daily Energy Expenditure (TDEE), your maintenance calorie level. A goal adjustment is then applied: −500 kcal for weight loss (approximately 0.5 kg/week deficit), 0 for maintenance, or +300 kcal for lean muscle gain.

Ketogenic macros are allocated from the adjusted calorie budget. Net carbs are set by your chosen limit (20–50 g/day is the standard ketogenic range that induces nutritional ketosis in most people; 4 kcal/g). Protein is set at 0.8 g per pound of body weight — a widely recommended midpoint for body-composition maintenance on keto (4 kcal/g). All remaining calories are assigned to fat (9 kcal/g), which typically lands at 60–75% of total calories on a well-formed ketogenic diet.

All figures are estimates. The Mifflin-St Jeor formula has a typical error of ±10%; individual metabolic rates vary. Activity multipliers are population averages, not personalised measurements. The 0.8 g/lb protein target is an editable guideline — highly active or strength-training individuals may benefit from 1.0 g/lb or higher. Net carbs means total carbohydrates minus dietary fibre (and optionally sugar alcohols). These outputs are a starting point; adjust over 2–4 weeks based on real weight change and ketone readings. Consult a registered dietitian for clinical dietary advice.