Tools · Fuel
Calorie and macro calculator
How much to eat each day, and in what split, from your body, your training and your goal. Built on the equations that measure closest in people who train.
Each day
Enter your age, height and weight to see your numbers.
Educational, not medical advice. If you have diabetes, a heart condition or another medical condition, ask your doctor or a dietitian first.
How it works, and how accurate it is.
Resting energy comes first, from whichever equation measures closest for you. With body fat, the Cunningham equation from fat-free mass. If you train, the ten Haaf equation, the most precise in a 2023 meta-analysis of athletes, where the popular Mifflin–St Jeor equation came out low. If you do not train, Mifflin–St Jeor, the most accurate in the general population. Even the best is within 10% of a lab measurement for about four people in five.
Maintenance is resting energy times your activity level, from the levels the FAO, WHO and UN University use. To lose fat, about 20% under maintenance: the rate at which athletes lost around 0.7% of their weight a week and kept their muscle. It never goes below your resting energy. To build muscle, 10% over, the bottom of the range for gaining without much fat.
Protein follows the sports nutrition research: more when losing fat, to hold on to muscle. Fat is 25% of energy, never under 20%. Carbohydrate is the rest, checked against what the guidelines give for your training.
Treat the result as a starting point. Weigh yourself across two or three weeks and adjust by about 100–200 kcal if your weight moves differently from the goal. px adjusts the food each day to the training you actually do.
Sources
- O'Neill JER, Corish CA, Horner K. Accuracy of resting metabolic rate prediction equations in athletes: a systematic review with meta-analysis. Sports Med. 2023;53(12):2373–2398.
- ten Haaf T, Weijs PJM. Resting energy expenditure prediction in recreational athletes of 18–35 years: confirmation of Cunningham equation and an improved weight-based alternative. PLoS One. 2014;9(10):e108460.
- Cunningham JJ. A reanalysis of the factors influencing basal metabolic rate in normal adults. Am J Clin Nutr. 1980;33(11):2372–2374.
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247.
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775–789.
- FAO, WHO, UNU. Human energy requirements: report of a joint FAO/WHO/UNU expert consultation. Food and Nutrition Technical Report Series 1. Rome: FAO; 2004.
- Garthe I, Raastad T, Refsnes PE, et al. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011;21(2):97–104.
- Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154.
- Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc. 2016;48(3):543–568.
- Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097.
Questions
How many calories should I eat to lose fat while training?
About 20% under your maintenance, which for most people loses roughly 0.5–1% of body weight a week. Faster than that tends to cost muscle and performance. The calculator never sets you under your resting energy.
Which BMR equation is most accurate?
It depends on who you are. For people who train, the ten Haaf equation, or Cunningham if you know your body fat, came out most accurate in a 2023 meta-analysis of athletes. In the general population, Mifflin–St Jeor. All are estimates: about one person in five sits more than 10% away from what a lab would measure.
What macro split should I use?
Set protein from your weight first, keep fat at 20–35% of calories, and let carbohydrate fill the rest, scaled to how much you train. A fixed ratio like 40/30/30 ignores how heavy you are and how hard you train.
How accurate are calorie calculators?
Within about 10% for most people. Use the number for two or three weeks, watch your weight, and adjust. Your scale is the final word, not the equation.
Tomorrow morning, already decided.
Seven days free. By this time next week, px knows your normal.