Calorie Calculator — Daily Calorie Target + Macros

How Your Daily Calorie Target Is Built

A daily calorie target starts from your resting metabolism (BMR) and scales it up to account for your actual weekly movement pattern. The resulting number is your estimated Total Daily Energy Expenditure — the amount of energy you burn in a typical 24-hour span. From that baseline, a controlled deficit or surplus is applied based on whether your goal is to lose, maintain, or gain weight. The 3,500-kcal-per-pound convention (about 7,700 kcal per kilogram) is used to convert weekly weight-change rates into per-day calorie shifts, as a population-level starting point.

Step 1 — BMR (Mifflin-St Jeor)

Basal Metabolic Rate is the energy your body needs to stay alive in a rested, thermoneutral, fasting state. We use the Mifflin-St Jeor equation (1990) because it is the most widely validated modern formula for the general adult population, with a typical accuracy of roughly ±10% in large groups. The formulas are: Male BMR = 10w + 6.25h − 5a + 5; Female BMR = 10w + 6.25h − 5a − 161, where w is weight in kilograms, h is height in centimeters, and a is age in years.

Step 2 — Activity Multipliers

Multiplying BMR by an activity factor converts resting energy into total daily expenditure. The standard bands are: Sedentary (1.2 — desk-bound, minimal movement), Lightly Active (1.375 — light exercise 1–3 days per week or active commute), Moderately Active (1.55 — 3–5 days of structured exercise per week), Active (1.725 — 6–7 days of exercise or a physical job), Very Active (1.9 — daily hard training combined with a physical role), and Athlete (2.0 — elite programming, often two training sessions per day). Choosing the band that most closely matches your average week rather than your best week is the key to a workable baseline.

Step 3 — Goal Adjustment

Step 4 — Macro Splits

Macro ratios turn a calorie number into grams of protein, carbohydrates, and fat using the standard caloric densities: 4 kcal per gram of protein, 4 kcal per gram of carbohydrates, and 9 kcal per gram of fat. The default Standard USDA split is 20% protein / 50% carbs / 30% fat. Alternative presets are provided as starting points, not rigid prescriptions. A balanced approach centered around minimally processed whole foods, adequate protein, and fiber-rich carbohydrate sources generally produces the most sustainable long-term outcomes for most people.

Why We Show Safe Floors

Very low daily calorie levels increase the risk of micronutrient gaps, muscle loss, hormonal disruption, rebound weight regain, and disordered eating patterns. For this reason, the calculator explicitly flags results below generally accepted reference floors of 1,200 kcal/day for adult females and 1,500 kcal/day for adult males. These are not personalized thresholds — they are population-level safety guards. Any sustained plan near or below these values should be designed and monitored by a qualified registered dietitian or wellness-focused care team member who can review your full health picture, Rx items you may use, and individual needs.