Body recomposition calculator

Calories use Mifflin-St Jeor, or Katch-McArdle when body fat is entered. Protein amounts come from the published ranges and estimates below, with each source shown beside its result.

Calculate maintenance and published protein amounts

The arithmetic at 180 pounds

The default example is male, age 35, height 5 feet 10 inches and moderately active. Calculations keep converted weight unrounded until the final result.

180 × 0.45359237 = 81.6466266 kilograms, displayed as 81.65.
70 × 2.54 = 177.8 centimeters.

Mifflin-St Jeor uses weight, height, age and the male constant.
10 × 81.6466266 + 6.25 × 177.8 − 5 × 35 + 5 = 1,757.716266.
Rounded BMR is 1,758.
1,758 × 1.55 = 2,724.9, rounded to 2,725 calories a day.

The ISSN endpoints are 1.4 and 2.0 times 81.6466266, rounded to 114 and 163 grams a day. Morton's 1.62 gives 132 grams, and its confidence interval upper value of 2.20 gives 180 grams.

At 20 percent body fat, fat-free mass is 80 percent of body weight.
81.6466266 × 0.80 = 65.31730128 kilograms, displayed as 65.32.
370 + 21.6 × 65.31730128 = 1,780.853707648.
Katch-McArdle BMR rounds to 1,781.
1,781 × 1.55 = 2,760.55, rounded to 2,761 calories a day.

Barakat's range multiplies 65.31730128 by 2.6 and 3.5. Rounded endpoints are 170 and 229 grams a day.

What recomposition meant in these studies

Barakat and colleagues described body recomposition as building muscle while losing fat. Their 2020 review included evidence in resistance-trained people, alongside discussion of untrained people and people with overweight or obesity. Progressive resistance training and nutrition were key factors in the studies.

The reviewed groups included aspiring female physique athletes, well-trained men and women, female collegiate volleyball players, elite male water polo players and rowers. These groups had different training programs and starting body composition. Most trials measured body composition with DEXA, and the review discussed limitations in those measurements.

Morton and colleagues pooled 49 trials with 1,863 healthy adults. The trials involved at least 6 weeks of resistance exercise and dietary protein supplementation. The reported effect on fat-free mass was larger in resistance-trained participants and smaller with increasing age. The ISSN position stand reviewed protein intake for healthy people who exercise.

Without a body fat number, the lean body mass calculator can still put a figure on lean mass. The FFMI calculator relates fat-free mass to height.

Three sources, two different weight bases

The ISSN position stand by Jäger and colleagues gives 1.4 to 2.0 grams per kilogram of body weight a day as sufficient for most exercising people to build or maintain muscle. Its summary describes that range as a minimum recommended amount. It also discusses evidence on intakes above 3.0 grams per kilogram in resistance-trained people.

The stand separately describes 2.3 to 3.1 grams per kilogram a day during periods of eating below maintenance for resistance-trained people seeking to retain lean mass. That below-maintenance range is outside this calculator's outputs.

Morton's estimated break point was 1.62 grams per kilogram of body weight a day. Its 95 percent confidence interval ran from 1.03 to 2.20. The break point analysis used 42 study arms with 723 participants and protein intakes from 0.9 to 2.4 grams per kilogram a day. The segmental regression was not statistically significant. The authors discussed 2.2 as a possible intake for those seeking the greatest training-related fat-free mass gains, using the upper end of the interval.

Barakat's review gives 2.6 to 3.5 grams per kilogram of fat-free mass as a range that may increase the likelihood or size of recomposition. It also describes recomposition evidence with resistance training and protein intakes above 2.0 grams per kilogram of body weight. The calculator uses the review's fat-free mass range, so it needs a body fat entry.

Why calories stay at maintenance

Barakat's review reported recomposition in studies with energy intake both below and above maintenance. It did not give a recommended calorie deficit or surplus. The authors said differences in methods and outcomes made specific guidance difficult to reconcile, and the precise energy cost of muscle growth was not fully known.

This page therefore returns the maintenance calculation from the TrueCal TDEE calculator. It does not adjust calories for recomposition. The calorie deficit calculator covers a different calculation, and the guide on building muscle in a calorie deficit discusses that question separately.

What these numbers do not estimate

There is no timeline, predicted muscle gain, predicted fat loss or training-day target here. Barakat's review says training status, the exercise program and starting body composition affect the size of the changes. A published protein range cannot tell an individual how their body will change.

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Questions about the calculator

What does this body recomp calculator return?

It returns estimated maintenance calories and protein amounts calculated from the ISSN position stand, Morton 2018 and Barakat 2020. Each protein figure keeps the body weight or fat-free mass basis used by its source.

Why does entering body fat change the calorie estimate?

A body fat entry selects Katch-McArdle, which uses fat-free mass. Without that entry, the calculator uses Mifflin-St Jeor with weight, height, age and sex.

Is the Morton upper figure a protein limit?

No. The 2.20 grams per kilogram figure is the upper end of the 95 percent confidence interval around the estimated break point. It is not a tested limit for an individual.

Can this calculator predict when recomposition will happen?

No. The Barakat review says training status, the exercise program and starting body composition affect how much muscle is gained and fat is lost. This calculator does not predict those changes or their timing.

Sources

Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990, volume 51, issue 2, pages 241 to 247. Checked October 19, 2026.

Jäger R, Kerksick CM, Campbell BI and others. International Society of Sports Nutrition Position Stand, protein and exercise. Journal of the International Society of Sports Nutrition, 2017, volume 14, article 20. Checked October 19, 2026.

Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SM. 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, 2018, volume 52, issue 6, pages 376 to 384. Checked October 19, 2026.

Barakat C, Pearson J, Escalante G, Campbell B, De Souza EO. Body Recomposition. Can Trained Individuals Build Muscle and Lose Fat at the Same Time? Strength and Conditioning Journal, 2020, volume 42, issue 5, pages 7 to 21. Checked October 19, 2026.

TrueCal TDEE calculator. Source of the activity multipliers and the Katch-McArdle equation used here. Checked October 19, 2026.