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Health Fitness

Weight Loss Calculator

Estimate weight loss with quick inputs.

Fast, practical estimates

Adjust inputs for the most useful result.

What this calculator does

The weight loss calculator is a personalized tool that determines how much weight you can realistically lose over a specific timeframe based on your current stats, activity level, and caloric deficit. It's designed for anyone looking to shed excess weight safely and sustainably. The calculator uses evidence-based formulas to estimate your daily caloric needs and then calculates the deficit required to reach your goal weight. Understanding the relationship between caloric deficit and weight loss helps you set realistic expectations and avoid crash diets or unsafe practices.

How it works

The calculator first determines your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) based on age, sex, height, weight, and activity level. It then asks you to set a target weight and timeline. A safe weight loss rate is typically 1-2 pounds per week, which requires a caloric deficit of 500-1000 calories daily (since 3,500 calories equals one pound of fat). The calculator creates your daily caloric target by subtracting the deficit from your TDEE.

Formula

BMR = 10(weight in kg) + 6.25(height in cm) - 5(age) + 5 for males (or -161 for females). TDEE = BMR × Activity Factor. Daily Calories for Weight Loss = TDEE - Caloric Deficit (500-1000). Target Timeline = (Current Weight - Goal Weight) × 3,500 calories per pound ÷ Daily Caloric Deficit.

Tips for using this calculator

  • Aim for a deficit of 500-750 calories daily for sustainable loss of 1-1.5 pounds per week without excessive hunger
  • Prioritize protein intake (0.7-1g per pound of body weight) to preserve muscle mass while in a caloric deficit
  • Combine calorie restriction with resistance training to maintain strength and muscle while losing fat
  • Track your progress weekly but expect natural fluctuations from water retention and hormones—focus on monthly trends
  • Adjust your caloric target every 5-10 pounds lost, as your metabolic needs decrease with lower body weight

Frequently asked questions

What's a safe rate of weight loss?

A safe, sustainable rate is 1-2 pounds per week, which typically requires a caloric deficit of 500-1000 calories daily. Faster weight loss increases risk of muscle loss, nutritional deficiencies, and metabolic adaptation.

Will I lose muscle while dieting?

Some muscle loss is inevitable during weight loss, but you can minimize it by maintaining adequate protein intake (0.7-1g per pound), doing resistance training regularly, and keeping your caloric deficit moderate.

Why does my weight fluctuate so much?

Weight naturally fluctuates 2-5 pounds daily due to water retention, hormones, glycogen levels, sodium intake, and digestive content. Focus on trends over 2-4 weeks rather than daily numbers.