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Calorie & Protein Calculator

Calorie Calculator

Find your maintenance calories, a deficit you can actually sustain, and the protein target that keeps muscle while you lose fat.

About you

Sex
Age (years)
Height (cm)
Weight (kg)

Activity & goal

Activity level
Goal

Your daily target

1,513kcal

A moderate deficit for steady fat loss while protecting muscle.

1,513 kcalMaintenance · 2,013 kcal

Pace

GentleAmbitious

−500 kcal/day → ≈ 0.5 kg/week (0.6%)

Maintenance

2,013kcalRoughly what you burn on an average day. · Resting (BMR) 1,464 kcal

Protein target

120–165g/day1.6 to 2.2 g per kg of bodyweight. Use a realistic goal weight if you carry a lot of body fat.

Daily step target

7,000 to 9,000Step range linked to lower mortality in large cohort studies [9].

This calculator gives population-based estimates for healthy adults and is for education, not medical or nutrition advice. Individual needs vary, and the equations are less accurate at the extremes of body size. Talk to a doctor or registered dietitian before starting a diet, especially with a health condition, an eating-disorder history, or during pregnancy.

Medical disclaimer

This tool estimates your maintenance calories (TDEE) with the Mifflin-St Jeor equation, then shows a moderate fat-loss deficit (about 300 to 500 kcal a day, roughly 0.5 to 1.0% of bodyweight a week) and a protein target of 1.6 to 2.2 g per kg of bodyweight to protect muscle. The numbers are starting points, not promises: your real burn varies and adapts, so track your results over two to three weeks and adjust.

The science behind the numbers

How big a deficit should you use?

Aim for a moderate deficit, roughly 300 to 500 kcal a day, which lands near 0.5 to 1.0% of bodyweight a week [6]. In a trial of athletes who also trained hard and ate plenty of protein, losing at about 0.7% a week preserved and even built muscle, while losing twice as fast did not [7]. Leaner people generally need the slower end of that range, while those carrying more fat can push a little harder. Cutting harder rarely speeds real fat loss; it mostly costs muscle and makes the diet harder to keep. Slower on the scale, better in the mirror.

Why the protein target matters

Protein is what keeps the weight you lose coming off as fat, not muscle. A sports-nutrition consensus puts the useful range for active people at 1.4 to 2.0 g per kg of bodyweight [3], and a meta-analysis places the point of diminishing returns for muscle near 1.6 g per kg, with little extra benefit beyond about 2.2 g per kg [4]. Reviews of lean dieters who train go higher still, to 2.3 to 3.1 g per kg of fat-free mass [5]. For most people, 1.6 to 2.2 g per kg of bodyweight is a sound target. Want a more detailed breakdown? Use our protein calculator.

Protein calculator

How this calculator works

Five quick inputs, three useful numbers. Here is what happens under the hood.

  1. 1You enter your sex, age, height, weight, activity level, and goal.
  2. 2We estimate your resting metabolism with the Mifflin-St Jeor equation [1], among the best-validated resting-energy formulas for healthy adults [2].
  3. 3We multiply that by an activity factor to estimate your maintenance calories, the total you burn on an average day.
  4. 4For fat loss we subtract a moderate deficit (about 300 to 500 kcal) and show the estimated weekly loss, because losing at roughly 0.5 to 1.0% of bodyweight a week protects muscle [6].
  5. 5We set a protein target of 1.6 to 2.2 g per kg of bodyweight to keep muscle while you lose fat [3, 4].

These are estimates, so treat them that way

Every formula here is a population average, and your real burn can sit above or below it, especially at the extremes of body size and in older adults. The weekly-loss figures use a simple rule of thumb (about 7,700 kcal per kg of fat); real loss is slower and tapers as your body adapts, so treat them as a rough guide, not a promise [10, 11]. Metabolism may also adapt after weight loss, with resting energy expenditure dropping by somewhat more than your smaller body explains, though how large and lasting that effect is remains debated [8]. The fix is not a fancier equation, it is feedback. Eat at your target for two to three weeks, track your weekly-average weight, and adjust by about 100 to 200 kcal if the trend is off.

Frequently asked questions

How accurate is a calorie calculator?

It gives a solid starting estimate, usually within about 10% for most healthy adults, but it is still an estimate. The Mifflin-St Jeor equation it uses [1] is among the best-validated for resting metabolism [2], though it is less accurate at the extremes of body size and less well validated in older adults. Your true burn also depends on genetics, muscle mass, and daily movement, so use the number as a starting point and adjust based on your weekly results.

What is the difference between BMR and maintenance calories?

BMR (basal metabolic rate) is what your body burns at complete rest just to keep you alive. Maintenance, or TDEE, is BMR plus everything else you do: walking, fidgeting, working out, digesting food. We multiply BMR by an activity factor to estimate maintenance, the number you eat around to hold your weight.

How big a calorie deficit should I use to lose fat?

A moderate one, about 300 to 500 kcal a day, which is roughly 0.5 to 1.0% of bodyweight a week [6]. Losing slower protects muscle: in one trial, the slower rate built muscle (alongside strength training) while the faster rate did not [7]. We never suggest eating below your resting metabolism.

How much protein should I eat while losing weight?

About 1.6 to 2.2 g per kg of bodyweight a day if you train [4]. A sports-nutrition consensus sets 1.4 to 2.0 g per kg as a solid floor [3], and reviews of lean dieters go to 2.3 to 3.1 g per kg of fat-free mass [5]. If you carry a lot of body fat, base the number on a realistic goal weight.

Why does my weight loss slow down even if I keep eating the same?

Partly because your maintenance drops as you get smaller, and partly because resting metabolism can fall by somewhat more than your size predicts (adaptive thermogenesis), although the size of that effect is debated [8]. Recalculate your numbers as you lose weight, protect muscle with strength training and protein, and read our weight-loss plateau guide for the full fix.

Sources

The formula and the calorie and protein targets are drawn from these peer-reviewed sources.

  1. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990). A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition. doi:10.1093/ajcn/51.2.241
  2. Frankenfield D, Roth-Yousey L, Compher C (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association. doi:10.1016/j.jada.2005.02.005
  3. Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition. doi:10.1186/s12970-017-0177-8
  4. Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. doi:10.1136/bjsports-2017-097608
  5. Helms ER, Zinn C, Rowlands DS, Brown SR (2014). A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. International Journal of Sport Nutrition and Exercise Metabolism. doi:10.1123/ijsnem.2013-0054
  6. Aragon AA, Schoenfeld BJ, Wildman R, Kleiner S, VanDusseldorp T, et al. (2017). International Society of Sports Nutrition position stand: diets and body composition. Journal of the International Society of Sports Nutrition. doi:10.1186/s12970-017-0174-y
  7. Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J (2011). Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. International Journal of Sport Nutrition and Exercise Metabolism. doi:10.1123/ijsnem.21.2.97
  8. Leibel RL, Rosenbaum M, Hirsch J (1995). Changes in energy expenditure resulting from altered body weight. New England Journal of Medicine. doi:10.1056/NEJM199503093321001
  9. Paluch AE, Bajpai S, Bassett DR, Carnethon MR, Ekelund U, et al. (2022). Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts. The Lancet Public Health. doi:10.1016/S2468-2667(21)00302-9
  10. Wishnofsky M (1958). Caloric equivalents of gained or lost weight. The American Journal of Clinical Nutrition. doi:10.1093/ajcn/6.5.542
  11. Hall KD, Chow CC (2013). Why is the 3500 kcal per pound weight loss rule wrong?. International Journal of Obesity. doi:10.1038/ijo.2013.112
  12. Jensen MD, Ryan DH, Apovian CM, Ard JD, Comuzzie AG, et al. (2014). 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults. Circulation. doi:10.1161/01.cir.0000437739.71477.ee

Stuck on a plateau, or losing muscle instead of fat?

Knowing your numbers is step one. Our guide shows what the research says about breaking a stall, keeping muscle, and not rebounding.

Read the plateau guide Protein calculator