Health Disclaimer
Last updated: February 2026
FitFixLife tools provide estimates only and are not a substitute for professional medical, nutritional, or fitness advice.
General Information
The calculators and tools provided on FitFixLife are intended for general informational and educational purposes only. They are based on published scientific formulas that have been widely used and studied, but they produce population-level estimates that may not perfectly reflect your individual physiology.
Not Medical Advice
Nothing on this website should be construed as medical, nutritional, or clinical advice. The results from our tools are not diagnoses and should not be used to self-diagnose or self-treat any medical condition. Always consult with a qualified healthcare professional, registered dietitian, or certified fitness trainer before making significant changes to your diet, exercise routine, or health regimen.
Formulas & Accuracy
Calorie Calculator
Uses the Mifflin-St Jeor equation (default) and Katch-McArdle formula (when lean mass is known). These are among the most accurate predictive equations for estimating Basal Metabolic Rate, but individual variance of 5–15% is normal.
BMI Calculator
Follows the WHO Body Mass Index classification. BMI does not distinguish between muscle mass and fat mass, and may not be appropriate for athletes, elderly individuals, or growing children.
Macro & Protein Calculators
Provide general percentage-based splits. Optimal macronutrient ratios depend on individual goals, training load, metabolic health, and medical conditions.
One-Rep Max Calculator
Averages seven published 1RM estimation formulas (Epley, Brzycki, Lombardi, Mayhew, O'Conner, Wathan, Lander). Estimates become less accurate above 10 repetitions and should not replace proper 1RM testing under qualified supervision.
Safe Calorie Minimums
Our calorie calculator enforces safe minimum thresholds: 1,500 kcal/day for males and 1,200 kcal/day for females. We will never recommend a daily intake below these levels. Very-low-calorie diets should only be undertaken with medical supervision.
Limitation of Liability
FitFixLife and its creators shall not be held liable for any injury, health complication, or adverse outcome resulting from the use of the information provided on this website. By using our tools, you acknowledge that you do so at your own risk and accept full responsibility for any decisions made based on the results.
Questions?
If you have questions about a specific calculation or the formulas we use, please contact us. We are happy to explain our methodology.