Calorie Calculator.
Calculate your daily calorie target using the Mifflin-St Jeor equation. Get maintenance, weight-loss and weight-gain numbers plus a recommended protein, carbs and fat split.
Enter your body weight in kilograms.
Enter your height in centimeters.
Updates instantly as you type. No data is sent to a server.
How to Use This Calculator
1. Pick your biological sex. The image cards apply the correct adjustment in the Mifflin-St Jeor formula automatically. 2. Set your age in years. 3. Enter your weight (kilograms) and height (centimeters) using the sliders. 4. Choose the Activity Level that best matches a typical week — be honest, this is the input that fluctuates the most. 5. Pick a Goal. Maintain shows your TDEE; Lose / Gain options apply a 500 or 1,000 kcal daily deficit / surplus, the safe range recommended by most weight-management guidelines.
Your Daily Calorie Target updates instantly. Beneath it, the calculator shows your BMR, your TDEE, and a starting macro split — protein, carbs, and fat — calculated against your target.
The Mathematical Foundation
Mifflin-St Jeor (1990, revalidated 2005): BMR (male) = 10·W + 6.25·H − 5·A + 5 BMR (female) = 10·W + 6.25·H − 5·A − 161 W = weight (kg) H = height (cm) A = age (years) Activity multipliers (Harris-Benedict 1990 update): Sedentary × 1.2 Light × 1.375 Moderate × 1.55 Active × 1.725 Athlete × 1.9 Daily target = (BMR × activity) + goal adjustment. Macro split (calories → grams): Protein = cals × 0.30 ÷ 4 Carbs = cals × 0.45 ÷ 4 Fat = cals × 0.25 ÷ 9 The energy density of each macro (4 kcal/g for protein and carbs, 9 kcal/g for fat) comes from Atwater factors, which are the values printed on every nutrition label.
Worked Examples
Example 1 — A 30-year-old male, 75 kg, 178 cm, moderate activity, maintenance. BMR = 10·75 + 6.25·178 − 5·30 + 5 = 1,717 kcal TDEE = 1,717 × 1.55 = 2,661 kcal Daily Target = 2,661 kcal
Example 2 — A 28-year-old female, 62 kg, 165 cm, light activity, lose 0.5 kg / week. BMR = 10·62 + 6.25·165 − 5·28 − 161 = 1,351 kcal TDEE = 1,351 × 1.375 = 1,858 kcal Daily Target = 1,858 − 500 = 1,358 kcal Macros ≈ 102 g protein, 153 g carbs, 38 g fat
Example 3 — A 22-year-old male athlete, 80 kg, 185 cm, gain 0.5 kg / week. BMR = 10·80 + 6.25·185 − 5·22 + 5 = 1,851 kcal TDEE = 1,851 × 1.9 = 3,517 kcal Daily Target = 3,517 + 500 = 4,017 kcal
Background
A calorie calculator estimates how much energy your body burns in a day so you can match your food intake to a goal — losing fat, holding steady, or building muscle. The number is built up in two stages: first your Basal Metabolic Rate (BMR), the calories you would burn lying still, and then your Total Daily Energy Expenditure (TDEE), which scales BMR by how active you are.
This calculator uses the Mifflin-St Jeor equation, the formula clinical nutritionists and registered dietitians have used as the gold standard since 2005. It is more accurate for the modern population than the older Harris-Benedict equation. The macronutrient breakdown that appears alongside your calorie target follows U.S. Institute of Medicine ranges (10–35 % protein, 45–65 % carbs, 20–35 % fat).
Frequently Asked Questions
How accurate is the Mifflin-St Jeor equation?
Within roughly ±10 % of measured BMR for a typical adult, which is more accurate than the older Harris-Benedict (1919) and Katch-McArdle equations for the general population. It is less accurate for people at the extremes of body composition (very lean athletes or people with high body-fat percentage). For those, an equation that uses lean body mass — like Katch-McArdle — is preferable.
Why does my calorie target feel high or low?
The biggest source of error is the Activity Level you pick. Most people overestimate it. If you have a desk job and exercise three or four times a week, Light is usually closer to the truth than Moderate. Try one level lower for two weeks; if your weight tracks where you expect, you have the right number.
Is a 1 kg / week weight loss safe?
A 1,000 kcal daily deficit is at the upper end of what most clinical guidelines consider safe for adults with a BMI above ~25. For people closer to a healthy weight, a 0.5 kg / week target is gentler and easier to sustain. Aggressive deficits cause more lean-mass loss and are harder to maintain long-term. Always check with a clinician if you have any medical conditions.
Should I recalculate as my weight changes?
Yes — every 4 to 6 weeks, or after every 4 kg change. As you lose weight your BMR drops because there is less tissue to maintain, so the same calorie target slows down progress. As you gain muscle the opposite happens. Calorie targets are starting points, not fixed numbers.
Do the macro percentages have to be exact?
No. The 30 / 45 / 25 split shown here is a general-purpose target that works for most goals. Endurance athletes typically push carbs higher; people on a ketogenic plan invert the carb/fat ratio. Hitting the calorie total reliably matters far more than hitting macros to the gram.