Knowing how many calories your body needs to maintain its current weight is the foundation of any nutrition plan, it is the baseline from which you adjust for weight loss, muscle gain, or simply staying where you are. A Maintenance Calorie Calculator estimates your Total Daily Energy Expenditure using the Mifflin-St Jeor equation, your sex, height, weight, age, and physical activity level. Beyond the calorie number, this tool also shows you how those calories distribute across carbohydrates, protein, and fat using a balanced 55/20/25 macro split, calculates your ideal weight based on a BMI of 22, and lets you enter a target weight to see exactly how many calories you would need to eat and how long it would take to get there. Whether you are maintaining, planning a change, or simply curious about your energy balance, Toolraxy provides a free, client-side calculator that gives you a complete nutritional starting point.
How to Use the Maintenance Calorie Calculator
Select your sex by clicking the Female or Male button.
Enter your height in centimeters, weight in kilograms, and age in years.
Choose your physical activity level from the dropdown: do not exercise, exercise regularly, physical job, or professional athlete.
Click Calculate. The tool displays your maintenance calories, a macro distribution (viewable as percentages or calories), and your ideal weight.
Optionally, enter a target weight to see the calorie adjustment needed and estimated time to reach that weight.
How the Tool Works
This Maintenance Calorie Calculator uses the Mifflin-St Jeor equation for Basal Metabolic Rate, multiplies by an activity factor to determine TDEE, distributes calories across macronutrients, calculates an ideal weight, and provides a weight change planner.
BMR Calculation (Mifflin-St Jeor Equation):
For males:
BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
For females:
BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
TDEE and Maintenance Calories:
TDEE = BMR × Activity Factor, rounded to the nearest whole number. Four activity levels are available:
I do not exercise: × 1.2
I exercise regularly: × 1.375
I have a physical job: × 1.55
I am a professional athlete: × 1.725
Macronutrient Distribution:
A balanced macronutrient split of 55% carbohydrates, 20% protein, and 25% fat is applied to the maintenance calories. Calorie values for each macronutrient are calculated by multiplying the TDEE by the respective percentage and rounding. Grams can be derived by dividing carbohydrate and protein calories by 4, and fat calories by 9. The results can be toggled between percentage view and calorie view.
Ideal Weight Calculation:
Ideal weight is calculated using a BMI of 22, which is the midpoint of the healthy BMI range (18.5–24.9):
Ideal Weight (kg) = 22 × (height in meters)²
Height is converted from centimeters to meters (÷ 100). The result is rounded to one decimal place.
Weight Change Planner:
When a target weight is entered, the calculator compares it to the current weight:
Weight difference = Target weight – Current weight
If gaining weight: add 500 kcal/day surplus. Estimated time = weight difference ÷ 0.5 kg per week.
If losing weight: subtract 500 kcal/day deficit. Estimated time = absolute weight difference ÷ 0.5 kg per week.
If already at target: display confirmation message.
The adjusted calorie target is displayed with the surplus or deficit amount and estimated weeks to goal.
Worked Example
Consider a 30-year-old male who is 170 cm tall, weighs 70 kg, and exercises regularly:
Male Mifflin-St Jeor BMR: (10 × 70) + (6.25 × 170) – (5 × 30) + 5 = 700 + 1,062.5 – 150 + 5 = 1,617.5, rounded to 1,618 kcal/day.
Activity factor (exercise regularly): 1,618 × 1.375 = 2,224.75, rounded to 2,225 kcal/day maintenance.
Macro split: Carbs 55% = 1,224 kcal, Protein 20% = 445 kcal, Fat 25% = 556 kcal.
Ideal weight: 22 × (1.70)² = 22 × 2.89 = 63.6 kg.
If target weight entered is 65 kg: weight difference = 65 – 70 = -5 kg (need to lose 5 kg). Adjusted calories: 2,225 – 500 = 1,725 kcal/day. Estimated time: 5 ÷ 0.5 = 10 weeks.
The user can toggle between seeing their macros as percentages (55/20/25) or as calorie values (1,224/445/556). The ideal weight of 63.6 kg provides a reference based on a healthy BMI midpoint. The weight change planner shows that reaching 65 kg would take approximately 10 weeks at a 500 kcal daily deficit.
Benefits of Using This Maintenance Calorie Calculator
Saves time by applying the Mifflin-St Jeor equation and macro split automatically.
Provides maintenance calories with a balanced 55/20/25 macronutrient distribution.
Toggles between percentage and calorie views for flexible macro tracking.
Calculates ideal weight based on a BMI of 22 for a healthy reference point.
Includes a weight change planner with calorie adjustments and time estimates.
Free and private, with all calculations running in your browser.
FAQs
How accurate is this maintenance calorie calculator?
The Mifflin-St Jeor equation is accurate to within about 10% for most people. Use the calculated number as a starting point and adjust based on your actual weight trends over 2–4 weeks.
What is the difference between BMR and maintenance calories?
BMR is the calories your body burns at complete rest. Maintenance calories (TDEE) include your BMR plus the energy you burn through daily activity, exercise, and digesting food.
Why is the macro split 55% carbs, 20% protein, and 25% fat?
This is a balanced distribution aligned with general dietary guidelines. It is suitable for most healthy adults. Athletes or those on specific diets may prefer different ratios.
How is ideal weight calculated?
Ideal weight uses a BMI of 22: 22 × (height in meters)². This is a general population reference, not a personalized target. Frame size and muscle mass affect what weight is healthy for you.
What if I want to lose or gain weight faster than 0.5 kg per week?
The calculator uses a 500 kcal daily adjustment as a sustainable rate. Larger deficits or surpluses can be effective short-term but should be approached with caution and ideally under professional guidance.
Can I use this calculator for a child or adolescent?
No. This calculator uses adult equations. Children and adolescents have different energy and nutrient needs and should be assessed by a pediatric healthcare professional.
Does this calculator store my personal data?
No. All calculations run entirely in your browser. No personal health data is saved or transmitted.
Can I share my maintenance calorie results?
Yes. Use the Copy button to copy all results, or the Share button to send a summary that includes your maintenance calories, macro split, and ideal weight.
Is this calculator a substitute for professional nutrition advice?
No. This tool provides estimates for educational purposes. Consult a registered dietitian or healthcare professional for personalized nutrition guidance.
How often should I recalculate my maintenance calories?
Recalculate every 3–6 months or after a significant weight change of 5 kg or more. As weight and body composition change, maintenance calories change as well.
