Body Recomposition Calculator
Body recomposition means you lose fat and gain muscle at the same time. Enter your details below. The calculator estimates your maintenance calories, a small-deficit target for training days and rest days, and daily protein, fat, and carb grams. It works for men and women, in metric or imperial units.
Your result
Enter your numbers and select "Calculate my recomp targets".
Set these macro targets in Calco
Enter your calorie, protein, carb, and fat goals once in Calco. Then snap a photo of each meal. Calco estimates the calories and macros, and you can adjust the portion. Free to download; photo logging requires the premium subscription.
Get Calco on the App StoreHow this calculator works
BMR = 10 x kg + 6.25 x cm - 5 x age + 5 (men) or - 161 (women). Maintenance = BMR x activity factor. Recomp average = maintenance x 0.90. Protein = 2.0 g/kg (or 2.5 g/kg lean mass). Fat = 25% of calories. Carbs = rest.
Step 1: BMR. The calculator estimates your basal metabolic rate (BMR) with the Mifflin-St Jeor equation. The equation comes from a 1990 study that measured the resting energy expenditure of healthy adults [1].
Step 2: maintenance. It multiplies the BMR by an activity factor from 1.2 (sedentary) to 1.9 (extra active). These are the common factors used with BMR equations. They are an approximation of the physical activity level (PAL) that the FAO/WHO/UNU expert report uses to estimate daily energy needs [2].
Step 3: a small deficit. The recomp target is 10% below maintenance as a weekly average. A recomposition needs two things: progressive resistance training and a suitable diet [5]. A large deficit makes muscle gain harder. For a full diet, Helms et al. advise a rate of loss of about 0.5 to 1% of body weight per week to keep muscle [4]. A recomp aims for a slower rate than that.
Step 4: training and rest days. Training days get 15% of maintenance more calories than rest days. The weekly average does not change. The extra calories come from carbohydrate, so you have more fuel on the days you lift.
Step 5: protein. The International Society of Sports Nutrition (ISSN) states that 1.4 to 2.0 g of protein per kg of body weight per day is sufficient for most people who exercise. It states that 2.3 to 3.1 g/kg may help resistance-trained people keep lean mass when they eat below maintenance [3]. A meta-analysis by Morton et al. found no further gain in fat-free mass above about 1.6 g/kg per day, with an upper confidence limit near 2.2 g/kg [6]. The calculator uses 2.0 g per kg of body weight. If you enter your body fat, it uses 2.5 g per kg of lean mass, which is inside the 2.3 to 3.1 g/kg lean-mass range from Helms et al. [4]. This keeps the target realistic for people with more body fat.
Step 6: fat and carbs. Fat is 25% of the average calories, inside the 15 to 30% range from Helms et al. [4]. The remaining calories come from carbohydrate.
Who it works best for. Many coaches say recomposition works only for beginners and people with more body fat. A 2020 review by Barakat et al. found that resistance-trained people can also build muscle and lose fat at the same time [5]. Beginners, people who return to training after a break, and people with a BMI of 25 or more (the NIDDK cutoff for overweight [7]) usually see the clearest change. Lean, advanced lifters can recomp too, but more slowly.
Limitations. The results are estimates. BMR equations predict the average for a group, so your real maintenance can be higher or lower. Body fat estimates from scales and calipers have errors. The calculator is for healthy adults. It is not medical advice. If you are pregnant, have a medical condition, or have a history of disordered eating, ask a doctor or a registered dietitian first.
Worked example
A 30-year-old man is 180 cm (5 ft 11 in) tall and weighs 80 kg (176 lb). He is a beginner, has a moderate activity level, and lifts 4 days a week.
- BMR = 10 x 80 + 6.25 x 180 - 5 x 30 + 5 = 1,780 kcal
- Maintenance = 1,780 x 1.55 = 2,759 kcal
- Recomp average = 2,759 x 0.90 = 2,483 kcal
- Training days = 2,483 + 0.15 x 2,759 x 3 / 7 = 2,660 kcal
- Rest days = 2,483 - 0.15 x 2,759 x 4 / 7 = 2,247 kcal
- Protein = 2.0 x 80 = 160 g
- Fat = 25% of 2,483 kcal / 9 = 69 g
- Carbs = about 350 g on training days and about 246 g on rest days
Over one week, 4 training days and 3 rest days give the same total as 7 days at 2,483 kcal.
How to track a body recomposition
Your weight can stay almost the same during a recomp, because you lose fat and gain muscle at the same time. Use more than the scale:
- Measure your waist once a week, at the same time of day.
- Record your main lifts. If your strength goes up while your waist goes down, the recomp works.
- Take progress photos every 2 to 4 weeks in the same light.
- Check your average weight over 2 weeks, not one day.
If your weight goes down fast and your lifts go down, eat more. If your waist goes up after 4 weeks, eat a little less on rest days.
Hit your macros without manual logging
A recomp depends on protein and calories that stay near the target every day. In Calco, you set your calorie and macro goals once. Then you snap a photo of each meal. Calco uses AI to estimate the calories, protein, carbs, and fat, and you can adjust the portion if it is not correct. Calco is free to download, and photo logging requires the premium subscription. It is available on iOS.
Frequently asked questions
How many calories should I eat for body recomposition?
Most recomp plans use a small deficit. This calculator sets your average intake 10% below your estimated maintenance, with more calories on training days and fewer on rest days. A larger deficit makes muscle gain harder [4] [5].
How much protein do I need for a body recomp?
The ISSN gives 1.4 to 2.0 g per kg of body weight per day for most people who exercise, and 2.3 to 3.1 g/kg for trained people who eat below maintenance [3]. The calculator uses 2.0 g/kg, or 2.5 g per kg of lean mass if you enter your body fat.
Is body recomposition possible for women?
Yes. The method is the same for women and men. The only difference in the calculator is the BMR equation, which uses a lower constant for women [1]. Select Female to get your targets.
Can experienced lifters recomp?
Yes, but it is usually slower. A 2020 review by Barakat et al. describes body recomposition in resistance-trained people when they train progressively and follow a suitable diet [5]. Beginners and people with more body fat usually see faster change.
How long does a body recomposition take?
There is no fixed time. Change is slow because you build muscle and lose fat at the same time. Track your waist, your lifts, and your 2-week average weight, and review your progress every few weeks.
Should I eat more on training days?
The calculator gives training days more calories, mostly from carbohydrate, and rest days fewer. The weekly total stays the same. If you prefer the same intake every day, eat the daily average target.
Do I need to know my body fat percentage?
No. Body fat is optional. If you enter it, the protein target uses your lean mass, which gives a more realistic number for people with more body fat.
Sources
- A new predictive equation for resting energy expenditure in healthy individuals (Mifflin MD et al., Am J Clin Nutr 1990), PubMed (NIH National Library of Medicine). Accessed October 18, 2026.
- Human energy requirements: Report of a Joint FAO/WHO/UNU Expert Consultation (2001), Food and Agriculture Organization of the United Nations (FAO). Accessed October 18, 2026.
- International Society of Sports Nutrition Position Stand: protein and exercise (Jäger R et al., 2017), PubMed Central (NIH National Library of Medicine). Accessed October 18, 2026.
- Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation (Helms ER et al., 2014), PubMed Central (NIH National Library of Medicine). Accessed October 18, 2026.
- Body Recomposition: Can Trained Individuals Build Muscle and Lose Fat at the Same Time? (Barakat C et al., Strength Cond J 2020), Strength and Conditioning Journal (NSCA). Accessed October 18, 2026.
- 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 (Morton RW et al., 2018), PubMed Central (NIH National Library of Medicine). Accessed October 18, 2026.
- Definition & Facts for Adult Overweight & Obesity, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Accessed October 18, 2026.
This calculator gives an estimate for general information. It is not medical advice. Read our editorial policy.