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Portion Size Calculator

Crop Yield Calculator

Calculate appropriate portion sizes based on your dietary goals, body metrics, and activity level

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Portion Size Calculator

What This Calculator Does

This calculator estimates your optimal daily calorie intake, macronutrient split, and portion sizes based on your gender, age, weight, height, activity level, and dietary goals. It outputs recommended servings of key food groups like protein, carbs, vegetables, fruits, dairy, and fats, split across your chosen number of meals.

Formulas Used
  • BMR (Mifflin-St Jeor):
    For males: BMR = 10×W + 6.25×H − 5×A + 5
    For females: BMR = 10×W + 6.25×H − 5×A − 161
  • TDEE: BMR × Activity Factor
  • Calorie Target: TDEE +/− Goal Adjustment (e.g. −500 for weight loss)
  • Protein: 4 cal/g, Carbs: 4 cal/g, Fat: 9 cal/g
  • Portions: Based on estimated grams per serving (e.g. 25g protein = 1 serving)
Example
  • Female, 65kg, 165cm, 30 years old, moderate activity
  • Goal: Mild weight loss, Meals/day: 3

BMR ≈ 1391 kcal
TDEE ≈ 1391 × 1.55 = 2156
Target Calories = 2156 − 250 = 1906 kcal
Macros: 40% protein, 35% carbs, 25% fat
→ 190g protein, 167g carbs, 53g fat
→ Daily portions ≈ 8 protein, 11 carb, 6 veggie, 3 fat, 2 fruit, 3 dairy

How to Use This Calculator
Step-by-Step Guide
  1. Select your gender, age, weight, and height
  2. Choose your activity level
  3. Select a dietary goal (e.g., maintain or lose weight)
  4. Set how many meals per day you prefer
  5. Click "Calculate Portion Sizes"
  6. Download your personalized plan as Excel or CSV
Tips for Better Accuracy
  • Use accurate weight in kilograms and height in centimeters
  • Choose an activity level that reflects your average week
  • Try different goals to compare portion needs
  • Stick to your selected number of meals/day when planning menus
Pro Tip: Use this plan alongside our Recipe Nutrition Calculator to balance your daily meals.
Frequently Asked Questions (FAQ)

It’s based on standard nutritional science and serves as a personalized baseline. For clinical advice, consult a registered dietitian.

Not in this version, but we’re working on a custom macro option in the next update!

Your total intake matters most. Skipping a meal will change your per-meal distribution, so adjust other meals to compensate.

The calculator includes plant-based, low-carb, and dairy-free alternatives. Adjust servings to fit your specific preferences or restrictions.