Calorie Calculator

Estimates your basal metabolic rate (BMR) and daily calorie needs (TDEE).

Sex

Age (years)

Height (cm)

Weight (kg)

Body fat (%, optional)

Only needed for the Katch-McArdle formula. Bioimpedance scales are imprecise: a 5-point error on a 65 kg person moves the result by roughly 70 kcal a day.

Formula

Activity level

Basal metabolic rate (BMR)

1,568 kcal

Daily calorie needs (TDEE)

2,155 kcal

Daily calories by goal
Goal	kcal per day	Weight change per week
Lose, −20%	1,724	-0.39 kg/week
Lose, −10%	1,940	-0.20 kg/week
Maintain	2,155	—
Gain, +10%	2,371	+0.20 kg/week
Gain, +20%	2,586	+0.39 kg/week

The weekly figure divides your daily surplus or deficit by 7,700 kcal per kg, the 1958 estimate for the energy stored in adipose tissue. It only holds for the first few weeks: as you lose weight your TDEE falls too, so real weight loss flattens out. The US NIH replaced this fixed rule with a dynamic model, the Body Weight Planner.

The 1.2 to 1.9 activity multipliers are a fitness-industry convention with no published derivation. FAO/WHO/UNU puts the sustainable floor for free-living adults at about 1.40, so a genuine desk job sits closer to 1.4-1.5 than to 1.2. These formulas predict a population average and your own figure can differ by roughly 10% either way. If the −20% row falls below your own BMR, read it as a warning rather than a target and speak to a doctor or dietitian.

To check whether your weight sits in a healthy range, see the BMI calculator

Calorie calculator

Estimates basal metabolic rate and daily calorie needs.

Calculates BMR from sex, age, height and weight, multiplies it by an activity factor to get TDEE, and shows daily intake targets from −20% to +20% with the initial rate of weight change.

The calculation runs in two steps: BMR first, then an activity multiplier.E.g. a 30-year-old man, 170 cm, 65 kg → Mifflin-St Jeor gives a BMR of 1,568 kcal; at moderate activity (×1.55) TDEE is 2,430 kcal.
Switching formulas moves the answer less than most people expect.Same person: Mifflin 1,568 / Harris-Benedict 1984 revision 1,605 / Katch-McArdle at 20% body fat 1,493 kcal — a spread of 115 kcal.
Switching activity level moves it far more.A BMR of 1,568 gives 1,882 kcal at ×1.2 and 2,430 kcal at ×1.55. That 549 kcal gap is larger than any formula choice.
The spread is slightly wider for women.A 30-year-old woman, 160 cm, 55 kg → Mifflin 1,239 / Harris-Benedict 1984 revision 1,322 / Katch-McArdle at 28% body fat 1,225 kcal.
Weekly change is the daily deficit divided by 7,700 kcal.From a TDEE of 2,430, a 20% cut is 1,944 kcal a day: 486 × 7 ÷ 7,700 ≈ 0.44 kg in the first week, tapering after that.
A low activity factor plus a deep cut can land below BMR.×1.2 with −20% gives 1,505 kcal, which is below the same person's predicted BMR of 1,568 kcal.

Basal metabolic rate (BMR): The minimum energy needed to keep the body running, measured fasted, at rest and lying down. What prediction equations such as Mifflin actually estimate is resting metabolic rate (RMR), which runs a few percent above true BMR.
Total daily energy expenditure (TDEE): BMR multiplied by an activity factor. The single multiplier lumps together exercise, everyday movement and the thermic effect of food, so it is an approximation rather than a measurement.
Physical activity level (PAL): TDEE divided by BMR. FAO/WHO/UNU reports that PAL values sustainable long-term by free-living adult populations range from about 1.40 to 2.40, and reserves roughly 1.21 for totally inactive dependent people in a crisis. Its own worked sedentary example — eight hours of sleep, eight hours of office work, light domestic activity — comes out at 1.53.
Mifflin-St Jeor equation: Published in 1990 from indirect calorimetry on 498 healthy adults aged 19 to 78. The 2005 systematic review by Frankenfield and colleagues found it the most accurate of the common equations in healthy adults, and it is the one the Academy of Nutrition and Dietetics recommends.
Katch-McArdle / Cunningham equation: 370 + 21.6 × fat-free mass, published by Cunningham in 1991 and popularised under the Katch-McArdle name by the McArdle, Katch and Katch exercise physiology textbook rather than derived in a study of that name. It is the most accurate option in this set when body composition is measured properly, and the least trustworthy when the body fat number is a guess.