Calorie Maintenance Calculator

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calorie maintenance calculator
Metric (kg, cm)Imperial (lb, ft/in)
MaleFemale
Sedentary (Office job, no exercise)Lightly Active (Exercise 1-3 days/week)Moderately Active (Exercise 3-5 days/week)Very Active (Exercise 6-7 days/week)Extra Active (Physical job + hard training)
Results:
kcal/day
function toggleUnits(){var units=document.getElementById('units').value;if(units==='metric'){document.getElementById('metricHeightRow').style.display='table-row';document.getElementById('imperialHeightRow').style.display='none';document.getElementById('weightLabel').innerHTML='Weight (kg):';}else{document.getElementById('metricHeightRow').style.display='none';document.getElementById('imperialHeightRow').style.display='table-row';document.getElementById('weightLabel').innerHTML='Weight (lb):';}}function calculateTDEE(){var units=document.getElementById('units').value;var gender=document.getElementById('gender').value;var age=parseFloat(document.getElementById('age').value);var weight=parseFloat(document.getElementById('weight').value);var activity=parseFloat(document.getElementById('activity').value);var h_cm=0;var w_kg=0;if(isNaN(age)||isNaN(weight)){alert('Please fill in all fields correctly');return;}if(units==='metric'){h_cm=parseFloat(document.getElementById('heightCM').value);w_kg=weight;}else{var ft=parseFloat(document.getElementById('heightFT').value)||0;var inch=parseFloat(document.getElementById('heightIN').value)||0;h_cm=((ft*12)+inch)*2.54;w_kg=weight/2.20462;}if(isNaN(h_cm)||h_cm<=0){alert('Please enter a valid height');return;}var bmr=0;if(gender==='male'){bmr=(10*w_kg)+(6.25*h_cm)-(5*age)+5;}else{bmr=(10*w_kg)+(6.25*h_cm)-(5*age)-161;}var tdee=bmr*activity;document.getElementById('resultValue').innerHTML=Math.round(tdee).toLocaleString();document.getElementById('bmrValue').innerHTML='Your Basal Metabolic Rate (BMR) is '+Math.round(bmr).toLocaleString()+' calories.';if(document.getElementById('steps').checked){var breakText='Detailed Breakdown:
1. Basal Metabolic Rate (BMR): '+Math.round(bmr)+' kcal
2. Activity Multiplier: '+activity+'x
3. Total Daily Energy Expenditure (TDEE): '+Math.round(tdee)+' kcal';document.getElementById('breakdown').innerHTML=breakText;document.getElementById('breakdown').style.display='block';}else{document.getElementById('breakdown').style.display='none';}document.getElementById('calculatorAnswer').style.display='block';}function resetCalc(){document.getElementById('calculatorAnswer').style.display='none';}

How to Use the Calorie Maintenance Calculator

The calorie maintenance calculator is a precision tool designed to estimate the number of calories your body needs daily to maintain its current weight. By balancing the energy you consume with the energy your body expends, you can achieve a state of "homeostasis" or weight stability.

To get started, simply input your vital statistics and activity level:

Gender and Age
Metabolic rates vary by sex and tend to decrease naturally as we age due to changes in muscle mass and hormone levels.
Height and Weight
Larger bodies require more energy to function and move. You can use either Metric (cm/kg) or Imperial (ft/in/lb) units.
Activity Level
This is a multiplier that accounts for physical movement, from a sedentary office job to high-intensity athletic training.

How the Calculation Works

This calorie maintenance calculator utilizes the Mifflin-St Jeor Equation, which is currently considered the most accurate standard for predicting Basal Metabolic Rate (BMR). Your maintenance calories, also known as Total Daily Energy Expenditure (TDEE), are calculated in two steps:

Step 1: Calculate BMR

Male: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
Female: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Step 2: Apply Activity Multiplier (TDEE)

Your BMR is then multiplied by an activity factor (PAL):

  • Sedentary (1.2): Little to no exercise.
  • Lightly Active (1.375): Light exercise 1-3 days/week.
  • Moderately Active (1.55): Moderate exercise 3-5 days/week.
  • Very Active (1.725): Hard exercise 6-7 days/week.
  • Extra Active (1.9): Very hard exercise or physical job.

Calculation Example

Scenario: Let's calculate the needs for a 35-year-old male, standing 5'10" tall, weighing 180 lbs, with a moderately active lifestyle.

Step-by-Step Breakdown:

  1. Convert Units: 180 lbs ≈ 81.65 kg | 5'10" ≈ 177.8 cm
  2. Calculate BMR: (10 × 81.65) + (6.25 × 177.8) – (5 × 35) + 5 = 816.5 + 1111.25 – 175 + 5 = 1,757.75 kcal
  3. Apply Activity: 1,757.75 × 1.55 (Moderately Active) = 2,724.51 kcal
  4. Result: Approximately 2,725 calories/day for maintenance.

Common Questions

How many calories should I eat to lose weight?

To lose weight, you generally need to create a calorie deficit. A common approach is to subtract 500 calories from your maintenance result, which theoretically leads to about 1 lb of weight loss per week.

Is this calorie maintenance calculator 100% accurate?

While based on scientifically validated formulas, it is an estimate. Individual metabolism can be affected by genetics, body composition (muscle vs. fat), and thyroid health. Use the result as a starting point and adjust based on your progress.

What is BMR versus TDEE?

BMR (Basal Metabolic Rate) is the energy your body needs just to keep your organs functioning while at complete rest. TDEE (Total Daily Energy Expenditure) is your BMR plus all the energy used for walking, talking, working, and exercising.

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