acalculator

What is my body recomposition goal?

Type your weight, body fat now, goal body fat, the lean mass you plan to add and your weekly fat loss. The body recomposition calculator finds your goal weight, the fat to lose, how many weeks it takes, and a protein range.

Your numbers

Units
Goal weight
164.7

At 15% body fat your goal weight is 164.7 lb, after losing 20.3 lb of fat in about 20.3 weeks.

Goal weight (kg)kg
74.7
Fat to loselb
20.3
Fat to lose (kg)kg
9.2
Weeks to goal
20.3
Fat mass nowlb
45
Fat mass now (kg)kg
20.4
Lean mass nowlb
135
Lean mass now (kg)kg
61.2
Protein per day, fromg
132
Protein per day, tog
180

Goal weight: 164.7. At 15% body fat your goal weight is 164.7 lb, after losing 20.3 lb of fat in about 20.3 weeks.

This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use

How to calculate

Splits your weight into fat and lean mass and finds your weight at a goal body fat percent after gaining muscle, the fat to lose, the weeks it takes, and a protein range.

Example with the default inputs (Weight 180 lb, Body fat now 25%, Goal body fat 15%, Lean mass to gain 5 lb, Fat loss per week 1 lb): At 15% body fat your goal weight is 164.7 lb, after losing 20.3 lb of fat in about 20.3 weeks.

Method: Fat mass = weight × body fat ÷ 100; lean mass = weight − fat mass; goal weight = (lean mass + lean gain) ÷ (1 − goal ÷ 100); fat to lose = fat mass − goal weight × goal ÷ 100; weeks = fat to lose ÷ fat loss per week; protein = 1.62 to 2.2 g × weight now in kg.

  • Body fat percents are as you type them; a scan, calipers and a tape measure can differ by several points.
  • Lean mass is everything that is not fat. The lean mass you gain is added to it, and none of it is lost on the way.
  • Fat comes off at the steady rate you type. Real progress is uneven; CDC suggests losing about 1 to 2 lb a week.
  • Protein: 1.62 g per kg a day is where extra protein stopped adding muscle in the Morton (2018) meta-analysis; about 2.2 g per kg is its upper estimate.
  • This is for information only and is not medical advice.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Weight 180 lb, Body fat now 25%, Goal body fat 15%, Lean mass to gain 5 lb, Fat loss per week 1 lb gives Fat mass now 45, Lean mass now 135, Goal weight 164.705882, Fat to lose 20.294118, Weeks to goal 20.294118, Protein per day, from 132.267535, Protein per day, to 179.622579.Source: Morton RW and others. 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. Br J Sports Med 2018;52:376–384 (1.62 g/kg/day; ~2.2 g/kg/day to maximise gains), https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/; CDC, Steps for Losing Weight (about 1 to 2 pounds a week), https://www.cdc.gov/healthy-weight-growth/losing-weight/index.html
  2. Weight 176.4 lb, Body fat now 20%, Goal body fat 15%, Lean mass to gain 0 lb, Fat loss per week 0.5512 lb gives Fat mass now (kg) 16, Lean mass now (kg) 64, Goal weight (kg) 75.294118, Fat to lose (kg) 4.705882, Weeks to goal 18.823529.Source: CDC, Steps for Losing Weight (about 1 to 2 pounds a week), https://www.cdc.gov/healthy-weight-growth/losing-weight/index.html
  3. Weight 154.3 lb, Body fat now 30%, Goal body fat 25%, Lean mass to gain 4.409 lb, Fat loss per week 1.102 lb gives Goal weight (kg) 68, Fat to lose (kg) 4, Weeks to goal 8, Protein per day, from 113.4, Protein per day, to 154.Source: Morton RW and others. 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. Br J Sports Med 2018;52:376–384 (1.62 g/kg/day; ~2.2 g/kg/day to maximise gains), https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/

How it works

With W your weight now, bf your body fat now and g your goal body fat (both as percents), and L₊ the lean mass to gain:

  • Fat mass = W × bf ÷ 100.
  • Lean mass = W − fat mass.
  • Goal weight = (lean mass + L₊) ÷ (1 − g ÷ 100).
  • Fat to lose = fat mass − goal weight × g ÷ 100.
  • Weeks to goal = fat to lose ÷ fat loss per week.
  • Protein per day = 1.62 g to 2.2 g × W in kg.

Masses typed in pounds are changed to kilograms at 1 lb = 0.45359237 kg exactly; pound results are kilograms ÷ 0.45359237. Each typed value is used as the exact decimal you typed, and each result is an exact fraction rounded once.

Rules

  • Weight from 30 kg to 350 kg; body fat now and goal body fat from 3% to 70%; lean mass to gain from 0 to 50 kg; fat loss per week from 0.01 kg to 2 kg. Each limit is included and is checked in kilograms: in pounds the weight is 66.14 lb to 771.61 lb, the lean gain at most 110.23 lb, and the weekly fat loss 0.03 lb to 4.4 lb (the two-decimal pound values inside the kilogram limits; 0.02 lb and 4.41 lb are outside).
  • When the fat to lose is 0 or less (the goal is not below your body fat now, or the lean mass to gain alone reaches it), the page gives no answer, with a message.
  • Lean mass is kept, plus the gain; the fat comes off at the steady weekly rate you type.

Output format. Masses show in pounds and kilograms with 1 decimal, weeks with 1 decimal, protein in whole grams, each rounded half up from its exact value. The US page heads the result with the goal weight in pounds; the Metric page, in kilograms.

Worked examples by hand

180 lb, 25% to 15%, +5 lb lean, 1 lb a week. Fat 180 × 0.25 = 45 lb; lean 135 lb. Goal = (135 + 5) ÷ 0.85 = 164.7 lb. Fat to lose = 45 − 164.71 × 0.15 = 20.3 lb, or 20.3 weeks. Protein: 180 lb = 81.647 kg; × 1.62 = 132 g to × 2.2 = 180 g a day.

80 kg, 20% to 15%, no lean gain, 0.25 kg a week. Fat 16 kg, lean 64 kg. Goal = 64 ÷ 0.85 = 75.3 kg. Fat to lose = 16 − 75.29 × 0.15 = 4.7 kg; ÷ 0.25 = 18.8 weeks.

70 kg, 30% to 25%, +2 kg lean, 0.5 kg a week. Fat 21 kg, lean 49 kg. Goal = 51 ÷ 0.75 = 68 kg. Fat to lose = 21 − 17 = 4 kg, 8 weeks. Protein 113 g to 154 g a day.

Other questions people ask

What is body recomposition?

Losing fat and gaining lean mass (mostly muscle) at the same time, so your body fat percent falls even if the scale moves little. It usually pairs strength training with enough protein and a small calorie deficit.

How is my goal weight found?

Your lean mass stays (plus any you gain), and fat makes up the goal percent of the new weight: goal weight = lean mass ÷ (1 − goal body fat). At 180 lb and 25% fat, lean mass is 135 lb; with 5 lb more at 15% fat, the goal weight is 140 ÷ 0.85 = 164.7 lb.

How much fat do I need to lose?

Your fat mass now less the fat mass at the goal weight. In the example: 45 lb − 164.7 × 0.15 = 20.3 lb. At 1 lb a week that takes about 20 weeks.

How much protein do I need for body recomposition?

A 2018 meta-analysis of strength training studies (Morton and others) found that extra protein stopped adding muscle at about 1.62 g per kg of body weight a day, and suggested up to about 2.2 g per kg. For 180 lb (81.6 kg), that is 132 to 180 g a day.

How fast should I lose fat?

CDC notes that people who lose about 1 to 2 lb a week are more likely to keep it off. When you are also building muscle, a slower pace is common.

Why does the page say my goal needs no fat loss?

If the goal body fat is not below your body fat now, or you plan to gain so much lean mass that it alone brings you to the goal, there is no fat to lose. Lower the goal or the lean mass to gain.