Body Recomp Calculator

Most nutrition advice forces a choice: bulk to build muscle, or cut to lose fat. This body recomp calculator is built for the alternative: doing both at once. Enter your stats and training background, and it returns a suitability read, training and rest day calorie targets, a protein target, and a realistic timeline for the fat you want to lose.

It's built for beginners and intermediate lifters wanting to improve their shape without a dedicated bulk or cut, returning lifters looking to regain lost muscle while dropping fat, and anyone deciding whether recomposition or a straight cut fits their situation better. Use the tool above to get your numbers, then read on for the research behind the approach, a worked example, and where recomposition tends to fall short.

1. How the Body Recomp Calculator Works

The calculator starts by estimating your basal metabolic rate (BMR), the energy your body burns at rest. If you enter a body fat percentage, it uses the Katch-McArdle formula, which is based on lean mass and is more accurate for people who know their body composition. Without it, the calculator falls back to the widely used Mifflin-St Jeor formula.

From there, your daily lifestyle activity (your job and general movement, not your weight training) sets a maintenance-calorie estimate. Your chosen approach (Near Maintenance or Modest Deficit) then sets separate training-day and rest-day targets, since your body needs more fuel on days it trains hard, and the calculator combines those with how many days a week you train into a weekly average. Keeping lifestyle activity and training separate avoids counting the same exercise twice. Protein is shown as a range, since individual needs vary, calculated from lean mass when body fat is known or from total bodyweight otherwise, since protein is the nutrient doing the most work in a recomposition.

If you provide both a current and target body fat percentage, the calculator also estimates the fat you need to lose and a realistic timeline, using a pace that depends on your training experience, since muscle (and the metabolic conditions that come with building it) is gained faster by beginners than advanced lifters.

2. How to Use the Body Recomp Calculator

1. Enter your sex, age, height, and weight, switching to metric if that's easier.
2. Add your body fat percentage if you know it (from a scale, calipers, or a body fat calculator). This unlocks the more accurate formula, the suitability read, and the timeline.
3. Add a target body fat percentage if you have one in mind, to see how much fat that represents and how long it might realistically take.
4. Select your training experience and activity level, and how many days a week you weight train.
5. Choose your calorie approach: Near Maintenance leans toward muscle gain, Modest Deficit leans toward faster fat loss, both within the range research suggests still allows muscle growth.
6. Read your results: suitability, training and rest day calories and macros, protein target, fat to lose, and estimated timeline. Download a PDF summary or copy your results if you want to track them elsewhere.

3. Body Recomp Calculator Formula

Calories:

Where the activity multiplier ranges from 1.2 (sedentary) to 1.9 (extremely active), following the standard Harris-Benedict activity scale. Training-day and rest-day calories then adjust from maintenance based on your chosen approach, keeping the gap between them inside the roughly 300-500 kcal range that research associates with still allowing muscle growth.

Protein and macros:

Protein is shown as a range rather than a single exact number, since individual needs vary within it. The midpoint of that range is what the fat and carb targets below are built around.

Fat to lose and timeline:

Fat to lose is calculated by assuming your lean mass holds steady (or grows slightly) through the recomp, then working out what your bodyweight would be at your target body fat % with that same lean mass. This gives a more accurate figure than simply multiplying bodyweight by the percentage-point difference, which understates the fat you actually need to lose. Weekly pace follows your training experience: faster for beginners, slower for advanced and elite lifters, reflecting how quickly each group can build the muscle that a recomp depends on.

4. Worked Example

Say you're a 30-year-old male, 180 lb at 20% body fat, targeting 15%, intermediate training experience, moderately active lifestyle (on your feet often, outside training), training 4 days a week, choosing Near Maintenance.

So this person would target roughly 2,431 kcal on training days, 2,084 kcal on rest days (a weekly average of about 2,282 kcal/day), 158 g of protein daily, and a realistic 6-7 month timeline to drop the 10.6 lb of fat while holding muscle.

5. Understanding Your Result

The scale is a poor progress marker during a recomp, since muscle gain and fat loss can roughly offset each other in total bodyweight. Track waist measurement, progress photos, and strength on your main lifts instead of relying on the number on the scale week to week.

If you don't enter a body fat percentage, you'll still get calorie and protein targets, but not a suitability read or timeline, since both depend on knowing where your body fat currently sits. A tape measure, calipers, or a body fat calculator are enough to get a usable estimate.

6. Who Recomp Actually Works For

A 2020 review in the Strength and Conditioning Journal confirmed that building muscle and losing fat at the same time is achievable, particularly for certain groups. Three groups see the best results: true beginners in their first year of structured resistance training, lifters returning after time off who are regaining muscle they've lost before, and undertrained lifters who have years of gym attendance but haven't trained hard or eaten well enough to see real progress.

Higher body fat also helps, since it gives the body more stored energy to draw on while building muscle. As a rough guide, men under about 15% body fat and women under about 22-25% tend to have a harder time recomping and may see faster results from a dedicated cut or lean bulk instead.

7. Practical Tips

• Prioritize protein above everything else. It's the nutrient with the most research support for protecting and building muscle in a deficit or at maintenance.
• Track measurements, not just the scale. Waist circumference, progress photos, and how your clothes fit are more reliable recomp signals than bodyweight alone.
• Train with progressive overload. Gradually increasing weight, reps, or volume over time is what actually signals your body to build muscle, regardless of your calorie target.
• Get enough sleep. Research links poor sleep to worse fat loss and blunted muscle gain even when nutrition and training are dialed in.
• Reassess every 4-6 weeks. Your maintenance calories shift as your body composition changes, so recalculate periodically rather than running the same numbers for months.

8. Common Mistakes

• Judging progress by the scale alone. A stable or even slightly rising weight can still represent real fat loss if muscle is being added at the same time.
• Cutting too hard. A large calorie deficit undermines the muscle-building side of a recomp; research suggests gains slow sharply past roughly a 300-500 kcal deficit.
• Under-eating protein. In a deficit or at maintenance, too little protein means your body has less material available to build or preserve muscle.
• Expecting bulk-and-cut speed. Recomposition is slower than a dedicated cut because you're not in a large deficit; patience is part of the method, not a sign it's failing.
• Ignoring training experience. An advanced lifter expecting beginner-speed muscle gain will likely become discouraged well before real progress shows up.

9. Related Calculations and Use Cases

Body composition and fitness testing often go hand in hand, since many fitness standards factor in body composition alongside raw performance. If you're also working through a fitness assessment, our PFT Calculator can help with that side of the picture.

Common real-world use cases for this calculator include a first recomposition attempt after months of inconsistent training, returning to the gym after a layoff and wanting to regain lost muscle while leaning out, and deciding between a recomp and a dedicated cut before starting a structured program. Each of these points to a different calorie approach and timeline, which is why both are kept as adjustable inputs above.

10. Frequently Asked Questions

This calculator provides general fitness information, not medical or nutrition advice. Individual results vary. If you have a medical condition, are pregnant or breastfeeding, or have a history of disordered eating, talk to a doctor or registered dietitian before changing your diet or training.