Calorie Calculator
Estimate how many calories you burn in a day from your age, sex, height, weight and activity level, and get a daily intake target for maintaining, losing or gaining weight. That is the CICO method. CICO stands for calories in, calories out, the idea that your weight follows the gap between the energy you eat and the energy you burn. This calculator covers the calories-out side and the target. Counting what you eat is left to you.
How to use the Calorie Calculator
- Enter your numbers in the Calorie Calculator above.
- Press the Calculate button to see the result.
- To try other numbers, change any value and press the button again.
The Mifflin–St Jeor equation
BMR (men) = 10·W + 6.25·H − 5·A + 5 · · · BMR (women) = 10·W + 6.25·H − 5·A − 161 · · · TDEE = BMR × activity factor
W is weight in kg, H is height in cm, A is age in years. The activity factor is 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active and 1.9 for extra active. The calculator shows BMR times that factor as your maintenance calories. It subtracts 250 and 500 kcal for the two loss targets and adds 500 kcal for the gain target.
Worked example
A 30-year-old man weighing 80 kg at 180 cm: BMR = 10×80 + 6.25×180 − 5×30 + 5 = 1,780 kcal. Moderately active (×1.55), his TDEE is about 2,759 kcal. For weight loss at a 500 kcal deficit, the target is ~2,259 kcal per day.
Using this as a CICO calculator
Calories out is the half of CICO you can't read off a food label, so it is the half this calculator estimates. It runs the Mifflin–St Jeor equation on your age, sex, height and weight and multiplies the result by your activity factor. The product is your maintenance figure, the same number a TDEE calculator reports as total daily energy expenditure.
Calories in is your side. The four result tiles give you an intake to aim for: maintenance, 250 kcal below it, 500 kcal below it and 500 kcal above it. Nothing here logs meals. You count what you eat with a food diary or a tracking app and compare the total with the tile you chose. For any other target, type your own figure in the box under the tiles: -400 is 400 kcal below maintenance.
What the calculator does not account for
The calories-out figure comes from an equation. Nobody measured you. Mifflin and colleagues derived the equation in 1990 from 498 healthy adults aged 19 to 78, and weight, height, age and sex explained 71% of the variation in resting energy expenditure between those people. The equation leaves the other 29% unexplained, so two people who enter the same numbers get the same result even if their bodies burn different amounts. The activity factor is cruder. There are five categories and you pick your own.
The result is also a snapshot. Weight is an input, so every kilogram you lose takes 10 kcal a day off the resting estimate, about 4.5 kcal per pound, before the activity factor multiplies it. An intake that sat 500 kcal below maintenance at your starting weight sits less than 500 below once you weigh less. Run the numbers again as your weight changes.
The calculator knows nothing about your health, your medication or your history with food. Which deficit is right for you, if any, is a question for a doctor or a registered dietitian.
Where the 1 lb per week labels come from
The loss and gain tiles carry estimated rates such as about 0.5 lb/wk and about 1 lb/wk. They come from the 3,500 kcal rule, which says a deficit of 3,500 kcal equals one pound of body weight, about 0.45 kg. At 500 kcal a day that is one pound in seven days. The metric labels round this to 0.25 and 0.5 kg.
Read the labels as rough arithmetic. Thomas and colleagues, who call it Wishnofsky's rule after a 1958 paper in the American Journal of Clinical Nutrition, compared its predictions with the weight people lost in seven experiments where intake was supervised or measured. Writing in the International Journal of Obesity in 2013, they concluded that the rule overestimates weight loss. Kevin Hall modelled the rule in the same journal in 2008. His model roughly matched the rule for people who start with more than 30 kg of body fat. For people with less body fat, the rule overstated the deficit needed for each pound lost.
The same estimate, one step at a time:
Frequently asked questions
Is this a CICO calculator?
Yes, for the calories-out half. CICO means calories in, calories out. The calculator estimates the calories you burn in a day and turns that into an intake target for maintaining, losing or gaining weight. It does not track what you eat, so counting the calories in is up to you.
How many calories should I eat to lose weight?
Fewer than your maintenance figure. The calculator shows two options, 250 and 500 kcal a day below maintenance, and labels them 0.5 lb and 1 lb per week using the 3,500 kcal per pound rule. Thomas and colleagues compared that rule with seven weight loss experiments where intake was supervised or measured, and reported in the International Journal of Obesity in 2013 that it overestimates weight loss. The weekly figure on the tile is rough. The calculator cannot judge which deficit suits your health. Ask a doctor or a registered dietitian. A loss target under 1,200 kcal a day for a man, or 1,000 for a woman, is below the lowest diet the NHLBI's weight-loss guide recommends. The calculator marks that tile and adds a note to plan it with a doctor.
What does TDEE minus 400 mean?
Your maintenance figure here is your TDEE, so it means eating 400 kcal a day below that figure. Type -400 in the box under the tiles. For the man in the worked example, 2,759 − 400 = 2,359 cal/day. A figure above 0 adds calories instead. By the 3,500 kcal per pound rule a 400 kcal deficit is about 0.8 lb a week, or about 0.4 kg in metric. The answer above gives the study that found the rule overestimates weight loss. A target under 1,200 kcal a day for a man, or 1,000 for a woman, gets the same mark as a tile.
What is TDEE?
Total Daily Energy Expenditure is the number of calories you burn in a day, including your basal metabolic rate plus activity, digestion and exercise. It is the number on the Maintain Weight tile.
Which calorie formula is most accurate?
A 2005 systematic review by Frankenfield, Roth-Yousey and Compher looked at the four equations most used in clinical practice: Harris–Benedict, Mifflin–St Jeor, Owen and WHO/FAO/UNU. Mifflin–St Jeor predicted resting metabolic rate within 10% of the measured value in more nonobese and obese adults than any other equation, and it had the narrowest error range. The review also notes that older adults and US-residing ethnic minorities were underrepresented in the studies. Indirect calorimetry measures resting metabolic rate, where an equation can only estimate it. This calculator uses Mifflin–St Jeor. Source: Journal of the American Dietetic Association, volume 105, issue 5.