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Calorie Calculator

Enter sex, age, height, weight and activity level to get BMR, TDEE and three goal calorie targets.

Whether the goal is losing fat or gaining muscle, the first step is neither eating less nor training more but knowing what is actually burned in a day — without that figure, calorie control is guesswork. Enter sex, age, height, weight and usual activity, and the resting metabolic rate comes first, scaled by activity into a daily total, with three targets for cutting, maintaining and bulking.

On the convention: the cutting target is set at −500 kcal a day, about the safe rate of half a kilogram of fat a week, and a more aggressive deficit is not advised; the bulking target of +300 kcal is the lean-gain convention, avoiding a large simultaneous gain in fat. All three are starting estimates — adjust them after two or three weeks against what the scale actually does.

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How to use

  1. Enter sex, age, height, weight and activity level.
  2. Read the BMR and the daily total.
  3. Compare the three goal targets.
  4. Adjust after two or three weeks against actual weight change.

How it works

How BMR is computed (Mifflin-St Jeor)

Basal metabolism uses the Mifflin-St Jeor formula: men's BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5; women replace the final +5 with -161. For a 70 kg, 175 cm, 30-year-old man, BMR = 700 + 1,093.75 - 150 + 5 = 1,648.75 kcal — what you'd burn lying still all day.

How to choose the activity factor

Daily total expenditure TDEE = BMR x activity factor. The five factors are sedentary 1.2, light 1.375, moderate 1.55, high 1.725 and very high 1.9. In the same example, exercising 3-5 times a week (moderate) gives TDEE = 1,648.75 x 1.55 = about 2,555.6 kcal. When unsure, choose a lower tier and correct by weight change.

Target calories and the safety floor

Target calories: fat loss subtracts 500 kcal from TDEE (about 0.5 kg a week), muscle gain adds 300. A 1,200 kcal safety floor applies to fat-loss calories — going below long-term should be under a doctor's or registered dietitian's guidance, or muscle loss, metabolic adaptation and rebound follow.

Calculation basis: BMR uses the Mifflin-St Jeor formula with activity factors from 1.2 to 1.9, and the weight-loss / muscle-gain adjustments follow the common −500 kcal / +300 kcal guidance. Results are estimates within roughly ±10% and do not replace advice from a doctor or registered dietitian.

Code example

JavaScript TDEE and three target levels 

function targets({ male, age, hCm, wKg, activity }) {
  const s = male ? 5 : -161;
  const bmr = 10 * wKg + 6.25 * hCm - 5 * age + s;   // Mifflin-St Jeor
  const tdee = bmr * activity;                        // 1.2~1.9
  return {
    bmr, tdee: Math.round(tdee),
    cut: Math.round(tdee - 500),                      // fat loss
    maintain: Math.round(tdee),
    bulk: Math.round(tdee + 300)                      // muscle gain
  };
}

Python The same formulas in Python 

def targets(male, age, h_cm, w_kg, activity):
    s = 5 if male else -161
    bmr = 10 * w_kg + 6.25 * h_cm - 5 * age + s
    tdee = bmr * activity
    return {"bmr": bmr, "tdee": round(tdee),
            "cut": round(tdee - 500), "bulk": round(tdee + 300)}

# activity: 1.2 sedentary / 1.375 light / 1.55 moderate / 1.725 very active / 1.9 extra active

FAQ

How does BMR differ from TDEE?

BMR is basal metabolism, the calories needed lying still to sustain life; TDEE is total daily expenditure = BMR x activity factor, including walking, work and exercise. Diet should follow TDEE; using BMR as the standard computes too low.

Why subtract 500 kcal for fat loss?

1 kg of fat is about 7,700 kcal, so 500 less a day roughly corresponds to 0.5 kg a week, a more sustainable rate. Losing too fast sheds muscle and water and rebounds more easily.

Why don't I lose weight eating this number?

Three common reasons: the activity factor is set too high; food logging underestimates (cooking oil, drinks and snacks are most often missed); and daily activity unconsciously drops after dieting. Record weight for 2-4 weeks and infer your real TDEE from actual change.

How much extra to eat to gain muscle?

About 300 kcal above TDEE, with strength training. Eating much more just adds fat: keeping weekly weight gain at 0.25-0.5% is reasonable during a muscle-gain phase, with 1.6-2.2 g of protein per kg of body weight.

Can it be used during pregnancy and breastfeeding?

Not applicable. Pregnancy and breastfeeding have dedicated energy recommendations (mid-to-late pregnancy usually needs several hundred extra calories) and must be assessed by a doctor — don't compute yourself with a general adult formula.

Is this formula accurate?

Mifflin-St Jeor is currently regarded as one of the more accurate estimates, but individual variation can still reach +/-10%: those with high muscle mass are often underestimated, those with higher body fat overestimated. Treat it as a starting point and calibrate with a 2-4 week weight trend.

Are my height and weight uploaded?

No. The whole calculation is a few multiply-adds done in your browser, not uploaded; the site has no account system linking your data either. If you used history, records live only in your browser, clearable in one click and gone on close in incognito mode.