Weight Loss Equations Calculator

BMI equals weight in kg divided by height in meters squared

Solution

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How It Works

This calculator bundles five weight-management equations. BMI screens body fat from height and weight. The Harris-Benedict BMR equations estimate calories burned at rest. Body fat percentage compares lean mass to total weight. TDEE multiplies your BMR by an activity factor to estimate total daily calorie needs.

Example Problem

A 30-year-old male weighs 80 kg and is 180 cm tall. What is his BMI and BMR?

  1. BMI = 80 / (1.80)2 = 24.7 (normal range)
  2. BMR (male) = 66 + (13.7 × 80) + (5 × 180) − (6.8 × 30) = 1,858 cal/day
  3. TDEE at moderate activity (1.55×): 1,858 × 1.55 ≈ 2,880 cal/day

Frequently Asked Questions

What is a healthy BMI range?

A BMI of 18.5–24.9 is considered normal weight. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese. BMI does not distinguish between muscle and fat, so athletes may score higher without excess fat.

How many calories should I eat to lose weight?

A common guideline is to eat 500 fewer calories per day than your TDEE, which produces about 1 pound of fat loss per week (3,500 calories = 1 lb). Losing more than 2 lbs per week is generally not recommended without medical supervision.

What is the difference between BMR and TDEE?

BMR is the calories your body burns at complete rest (just to keep organs functioning). TDEE adds the calories burned through daily activity and exercise. TDEE is always higher than BMR.

What is a healthy body fat percentage?

For men, 10–20% body fat is considered fit; for women, 18–28%. Essential fat minimums are roughly 3–5% for men and 10–13% for women. These ranges vary by age and fitness level.

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