Fitness & Body Composition Hub (New Zealand)
Fitness is defined by a balanced combination of cardiorespiratory health, muscular strength, and healthy body composition. Our fitness calculators provide scientific body metric tracking, calorie expenditure calculations, and nutrition planning. Whether your goal is to lose fat, build lean muscle, or optimize hydration, these tools are built on clinically-proven formulas to help you navigate your journey.
Core Fitness & Body Metrics Tools
- BMI Calculator - Determine your Body Mass Index (BMI) and health category.
- TDEE Calculator - Calculate your Total Daily Energy Expenditure (daily maintenance calories).
- BMR Calculator - Estimate your Basal Metabolic Rate (calories burned completely at rest).
- Body Fat Percentage Calculator - Track body composition using the US Navy tape method.
- Protein Calculator - Calculate optimal daily protein intake based on training intensity.
- Water Intake Calculator - Establish custom daily hydration targets by weight and climate.
- Walking Calorie Burn Calculator - Calculate calories burned based on speed, distance, and duration.
Clinical Guides & Insights
- BMR vs. TDEE: What's the Difference and Which Metric to Use?
- BMI vs. Body Fat Percentage: Understanding Health Risk Metrics
Scientific Citation & Outbound Authority: Body composition metrics are critical variables in sports medicine. Study the clinical definition and limitations of health indexing at Wikipedia's Body Mass Index Article.
Medically reviewed by Dr. Rekha Kumar, M.D., M.S. — Lead Medical Reviewer · Last reviewed: September 2026 · Updated: 2026-09-15
Evidence & references
This tool is for informational purposes only and is not a substitute for professional medical advice.
Frequently asked questions
Is this calculator free to use?
Yes. Every calculator on Weight Loss Percentage is free, with no sign-up or account required.
How accurate is the result?
Results depend on the accuracy of what you enter and the published formulas the tool uses, which follow standard guidance from national health authorities. Track the trend over weeks rather than relying on a single reading.
How often should I check it?
Check whenever your weight, activity or goals change — for most people once a week is enough to see a reliable trend.
Who reviews the content on this site?
All medical and nutrition content is written and reviewed by Dr. Rekha Kumar, M.D., M.S., our lead medical reviewer, and cites guidance from U.S. federal health sources such as the CDC and NIH.