Updated · Methodology: named formula library
Body Recomposition Calculator
Calculate calories and macros for simultaneous fat loss and muscle gain.
Value A to Value B = 4:1 (4 as decimal).
Why This Calculation Matters
The Body Recomposition Calculator takes the guesswork out of training by grounding decisions in actual math. Body composition, training load, and nutrition all interact, so revisit your numbers whenever your body or goals change meaningfully. A good target is a quick recomputation every 4-6 weeks.
How to Use This Calculator
- Enter your values in the input fields, each one has a label and help text explaining what to type.
- Results appear instantly as you type; there's no "calculate" button to press.
- Change any input to compare scenarios side by side.
All math happens in your browser. Nothing you type is sent to a server, saved, or shared.
How to Act on the Number
Treat the result as a starting point, then adjust by 50-100 calories (or equivalent) every couple of weeks based on real-world progress. Bodies adapt; your numbers should adapt with them.
How to Use the Body Recomposition Calculator
Enter the required values in the input fields on the left. Results update instantly on the right as you adjust your inputs.
Understanding Your Results
Review each output value and its description to understand how your inputs affect the outcome. Adjust values to compare different scenarios.
Tips
- All calculations happen in your browser, your data is never stored
- Bookmark this page for quick access
- Try different values to see how results change
Formula
Target calories = TDEE + surplus/deficit. A ~500 cal/day deficit produces roughly 1 lb of weight loss per week, though individual response varies with hormones, sleep, and activity.
Worked Example
100 Value A to 25 Value B
- a
- 100
- b
- 25
- Result
- 4:1 (4.00)
100 / 25 = 4.00. Simplified: 4:1.
When to Use This Calculator
- Program training around concrete targets instead of guesswork.
- Adjust nutrition and workload as your body weight or performance changes.
- Compare today's numbers to last week/month to spot meaningful trends.
Limitations & Common Mistakes
- Activity formulas assume typical body composition, very muscular or very lean individuals may see large deviations.
- Weight change in the first 1-2 weeks can reflect water and glycogen, not fat loss.
- Always progress load gradually and consult a physician before starting a new training program.
Frequently Asked Questions
How is the Body Recomposition Calculator computed?
Value A divided by Value B, plus a simplified ratio (e.g., 4:3) using greatest common divisor. Both decimal and ratio forms are useful in different contexts: decimal for math, ratio form for comparisons or recipe scaling.
What does Value A:Value B mean?
It's a comparison: for every Value B unit, you have a corresponding amount of Value A. Useful when the absolute numbers matter less than the proportion (e.g., reading 8:1 LTV/CAC immediately tells you the unit economics are healthy without needing the dollar amounts).
Why simplify the ratio?
4:3 is more readable than 200:150. The simplified form (using greatest common divisor) preserves the proportion while making it easier to interpret. Common simplified ratios: 16:9 (widescreen), 4:3 (legacy displays), 3:1 (LTV:CAC for SaaS).
When is a ratio more useful than the absolute values?
Comparison across scales. A $1B company and a $1M company can both have a 3:1 LTV:CAC; the ratio reveals comparable unit economics regardless of scale. Use ratios for benchmarking; use absolute numbers for budgeting.
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Source: BLS Consumer Price Index, 2026.