# Health & Fitness Calculator

> Four health tools in one: BMI with healthy range, Mifflin-St Jeor BMR and calorie targets, US Navy body fat, and heart-rate zones with hydration.

Free health and fitness calculator: BMI with category and healthy weight range, BMR and maintenance calories (Mifflin-St Jeor), weight-loss and muscle-gain targets, US Navy body fat percentage, heart-rate training zones and daily water intake.

- **Canonical:** https://www.ailovekit.com/calculators/health-fitness-calculator/
- **Category:** Calculator
- **Processing:** Runs entirely in your browser. Files are never uploaded to AiLoveKit servers.

## How It Calculates

- **Formula:** BMI = kg ÷ m²; BMR = 10w + 6.25h − 5a ± k (Mifflin-St Jeor)

All calculation runs locally in your browser; results update as you type and include the substituted working.

## Your Whole Health Dashboard

AiLoveKit's **health and fitness calculator** answers the four questions every fitness plan starts with: where does my BMI sit, how many calories do I burn, what is my body fat, and which heart-rate zone should I train in.

## Science-Based, Instantly Interactive

- **BMI** - category plus the healthy weight range for your height.

- **Calories** - BMR, maintenance, cut and bulk targets from Mifflin-St Jeor with five activity levels.

- **Body fat** - US Navy tape method with sex-specific formulas and category bands.

- **Training** - Tanaka max heart rate, five training zones, Karvonen target and daily hydration.

All four tools update as you type and every number shows its working. Tracking food costs too? The [Cooking Calculator](https://www.ailovekit.com/calculators/cooking-calculator/) scales recipes to match your plan.

## Frequently Asked Questions

**Which BMR equation is used?**

The Mifflin-St Jeor equation, the most accurate general-purpose formula for adults. It is multiplied by your activity level to get maintenance calories (TDEE).

**How accurate is the body fat estimate?**

The US Navy circumference method is typically within ±3% for most adults when tape measurements are taken at the described points.

**What do the calorie targets mean?**

Maintenance keeps your weight steady. About 500 kcal below maintenance loses roughly 0.5 kg per week; about 300 kcal above supports lean muscle gain.

**Is this medical advice?**

No - these are screening estimates for healthy adults. For medical decisions, pregnancy, or eating conditions, consult a healthcare professional.

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Source: https://www.ailovekit.com/calculators/health-fitness-calculator/
Part of AiLoveKit: https://www.ailovekit.com/
Machine-readable index: https://www.ailovekit.com/llms.txt