Evidence-Based Fitness Tools
Turn training and nutrition research into practical decisions. Use the free THG calculators to plan your macros, interpret your FFMI, or decide what to do with your weekly training volume.
What Are You Trying to Decide?
Each tool gives you a useful starting point, explains the result, and shows you what to do next. No sign-up is required.
Training Volume Calculator
Count your weekly work for one muscle, then use effort, progress, recovery, and wider training stress to choose your next adjustment.
- Direct and relevant indirect sets
- RIR explained in plain language
- Add, hold, reduce, or investigate
Macro Calculator
Build a 14-day starting plan for calories, protein, carbohydrates, and fats based on your body, activity, training, and goal.
- Muscle gain, fat loss, or maintenance
- Calories and macros calculated together
- Real-world adjustment guidance
FFMI Calculator
Estimate raw and normalized Fat-Free Mass Index and understand what the result can—and cannot—tell you about muscularity.
- Metric and imperial units
- Body-fat uncertainty included
- Population context and interpretation
More Than a Number
A calculator cannot know your body perfectly. THG tools therefore combine an estimate with context and a practical next step.
Clear Inputs. Honest Limits. Useful Decisions.
The goal is not to manufacture a perfect answer. It is to reduce guesswork while staying honest about what an equation can and cannot know.
Evidence-Based
Methods and recommendations are grounded in research and explained without hiding uncertainty.
Built for Real Lifters
Training, stress, activity, measurement error, and adherence matter outside the spreadsheet.
Designed to Be Reused
Return after collecting real-world data and make a more informed adjustment.
Turn the Number Into a Better Decision
A calculator gives you a starting point. Use the supporting guides below to interpret the result, understand its limitations, and decide what to do next.
Connect volume, effort, exercise selection, progression, and recovery within one practical system.
Explore the training hub → Interpretation What Is a Good FFMI?Compare your estimate with appropriate reference data without treating a category as a verdict.
Interpret your FFMI → Natural Potential How Much Muscle Can You Gain Naturally?Understand what influences long-term muscular potential and why no calculator can predict an exact ceiling.
Explore natural potential → Rate of Progress How Much Muscle Can You Gain in a Year?Set realistic expectations for yearly muscle gain based on experience, consistency, and recovery.
Estimate a realistic rate → Measurement DEXA vs InBodySee how measurement method, hydration, food, and testing conditions can change body-composition estimates.
Compare the methods →Choose the Decision You Need to Make
Plan your weekly training volume, set a nutrition baseline, or put your FFMI into context.