Estimate daily calories (TDEE) and protein, carb, and fat targets for your goal and activity level.

About the Calorie & Macro Calculator

Knowing how many calories your body burns in a day is the foundation of any deliberate change in weight, whether you are trying to lose fat, add muscle, or hold steady. This calculator estimates that number in two steps: it works out your basal metabolic rate (the energy you would burn lying in bed all day) and then scales it up by an activity multiplier to reach your total daily energy expenditure, or TDEE. From there it applies your goal to set a calorie target and splits that target into grams of protein, carbohydrate, and fat.

Rather than guessing, the tool uses the Mifflin-St Jeor equation, which validation studies have found more accurate than the older Harris-Benedict formula for modern populations. You provide sex, age, height, weight, an activity level, and a goal, and it returns three headline numbers (BMR, TDEE, and calorie target) plus a macronutrient breakdown you can build meals around.

How the Calorie & Macro Calculator works

For men the Mifflin-St Jeor BMR is 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5; for women the final constant is -161 instead of +5. That BMR is multiplied by an activity factor: 1.2 for sedentary, 1.375 for light, 1.55 for moderate, 1.725 for active, and 1.9 for very active work or training. The result is your TDEE, the calories that keep your weight stable.

The goal selector then adjusts TDEE by a fixed amount: -500 calories for weight loss, 0 to maintain, or +500 to gain. A 500-calorie daily deficit or surplus tracks the rule of thumb that about 3,500 calories equal a pound, so roughly a pound a week. The calorie target is finally divided into macros using a 30% protein, 40% carbohydrate, 30% fat split, converting calories to grams at 4 cal per gram for protein and carbs and 9 cal per gram for fat.

Worked example

Take a 30-year-old man, 175 cm, 72 kg, moderately active, aiming to lose weight. BMR is 10 x 72 + 6.25 x 175 - 5 x 30 + 5 = 720 + 1,093.75 - 150 + 5 = 1,669 calories. Multiplying by the moderate factor of 1.55 gives a TDEE of about 2,587 calories.

Applying the -500 weight-loss adjustment sets the daily target at roughly 2,087 calories. Split 30/40/30, that is about 156 g of protein (626 cal), 209 g of carbohydrate (835 cal), and 70 g of fat (626 cal). Hitting those numbers should drive close to a pound of loss per week while keeping protein high enough to protect muscle.

Tips & common mistakes

The activity multiplier is where most people go wrong; a desk job with three gym sessions a week is usually light-to-moderate, not active, so pick the lower option if you are unsure and adjust after two weeks of real-world results.
Protein at roughly 1.6 to 2.2 g per kg of body weight preserves lean mass in a deficit, so if the 30% figure lands below that range, nudge protein up and trim carbs or fat.
Recalculate every 4 to 6 kg of weight change; a lighter body burns fewer calories, so a target that worked at the start of a cut will stall you later.
Treat the output as a starting estimate, not gospel weigh weekly, average the readings, and change calories only if your trend disagrees with the prediction after 10 to 14 days.

Calorie & Macro Calculator: frequently asked questions

Why does the tool use Mifflin-St Jeor instead of Harris-Benedict?

The Mifflin-St Jeor equation was published in 1990 using a more representative sample and has been shown in comparison studies to predict resting energy expenditure within about 10% for more people than the older Harris-Benedict formula. It is the equation most registered dietitians default to today, which is why it drives this calculator.

Is a 500-calorie deficit safe?

For most adults a 500-calorie daily deficit is a moderate, sustainable rate that targets about a pound of fat loss per week without the muscle loss and hunger of aggressive cutting. If your target ever falls below roughly 1,200 calories for women or 1,500 for men, shrink the deficit, because eating too little makes adherence and nutrient intake difficult.

Why is the macro split 30/40/30?

It is a balanced, general-purpose ratio: enough protein to support training and satiety, enough carbohydrate to fuel workouts, and enough fat for hormone health. Low-carb or ketogenic dieters would shift carbs down and fat up, while endurance athletes might want more carbs, so treat the split as a sensible default you can tune.

Should I eat back the calories I burn exercising?

Not if you chose an activity multiplier that already reflects your training, because that exercise is baked into your TDEE. Eating back tracked workout calories on top of a moderate or active multiplier double-counts them and can erase your deficit. Only add calories if you selected sedentary and then did a genuinely unusual amount of activity.

How accurate is the calorie target?

Any equation is an estimate; real metabolic rate varies with genetics, non-exercise movement, and past dieting. Use the number as a two-week experiment, weigh yourself regularly, and adjust up or down by 100 to 200 calories based on your actual weight trend rather than assuming the prediction is exact.

Calorie & Macro Calculator