Calorie Calculator
The Calorie Calculator helps you estimate how many calories you need per day to maintain, lose, or gain weight based on your age, gender, height, weight, and activity level. It uses scientifically proven formulas such as Mifflin–St Jeor, Harris–Benedict, and Katch–McArdle to deliver accurate calorie targets for weight management. Ideal for fitness, diet planning, and healthy lifestyle tracking. Estimate daily calorie needs — choose a BMR formula, add an activity multiplier, then see calories for maintaining, losing or gaining weight. Uses the exact formulas (W = kg, H = cm, A = years, F = %).
About This Calculator
The Calorie Calculator helps estimate the number of calories your body needs each day to maintain, lose, or gain weight. It uses scientifically recognized formulas including the Mifflin–St Jeor Equation, Harris–Benedict Equation, and Katch–McArdle Formula to calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
By entering your age, gender, height, weight, activity level, and optional body fat percentage, you can receive personalized calorie recommendations for weight management and fitness planning.
What Is a Calorie Calculator?
A calorie calculator is a tool that estimates how much energy your body needs each day. Calories are units of energy that fuel essential body functions such as breathing, circulation, digestion, physical activity, and exercise.
Understanding your daily calorie requirements can help you make informed decisions about nutrition, weight loss, muscle gain, and overall health.
How Daily Calorie Needs Are Calculated
Daily calorie requirements are estimated using two steps:
- Calculate Basal Metabolic Rate (BMR)
- Apply an Activity Multiplier to estimate Total Daily Energy Expenditure (TDEE)
BMR represents the calories your body burns while at complete rest. TDEE includes BMR plus calories burned through movement, exercise, work, and digestion.
Common Activity Multipliers
- Sedentary: 1.2
- Lightly Active: 1.375
- Moderately Active: 1.55
- Very Active: 1.725
- Extra Active: 1.9
To lose weight, calorie intake is typically reduced below TDEE. To gain weight, calorie intake is increased above TDEE.
BMR vs TDEE Explained
Basal Metabolic Rate (BMR)
BMR is the number of calories your body requires to perform basic life-sustaining functions while at rest, including breathing, circulation, temperature regulation, and organ function.
For most individuals, BMR accounts for approximately 60%–75% of total daily calorie expenditure.
Total Daily Energy Expenditure (TDEE)
TDEE is the total number of calories burned throughout an entire day, including physical activity, exercise, daily movement, and digestion.
TDEE is generally the most useful number for planning calorie intake because it reflects your actual lifestyle and activity level.
- Eat at TDEE: Maintain weight
- Eat below TDEE: Lose weight
- Eat above TDEE: Gain weight
Mifflin–St Jeor Formula
The Mifflin–St Jeor Equation is widely regarded as one of the most accurate methods for estimating BMR in healthy adults and is often recommended by nutrition professionals.
Men:
BMR = (10 × Weight in kg) + (6.25 × Height in cm) − (5 × Age) + 5
Women:
BMR = (10 × Weight in kg) + (6.25 × Height in cm) − (5 × Age) − 161
Harris–Benedict Formula
The Harris–Benedict Equation is one of the oldest and most recognized methods for estimating calorie requirements. The revised version improves accuracy while maintaining simplicity.
Men:
BMR = 88.362 + (13.397 × Weight in kg) + (4.799 × Height in cm) − (5.677 × Age)
Women:
BMR = 447.593 + (9.247 × Weight in kg) + (3.098 × Height in cm) − (4.330 × Age)
Katch–McArdle Formula
The Katch–McArdle Formula estimates calorie needs using lean body mass rather than total body weight. It is often preferred by athletes and individuals who know their body fat percentage.
Step 1: Calculate Lean Body Mass
Lean Body Mass = Weight × (1 − Body Fat % ÷ 100)
Step 2: Calculate BMR
BMR = 370 + (21.6 × Lean Body Mass)
Frequently Asked Questions
How many calories should I eat per day?
Daily calorie needs vary based on age, gender, height, weight, activity level, and goals. This calculator provides an estimate tailored to your inputs.
Which formula is most accurate?
For most adults, the Mifflin–St Jeor Equation is considered the most accurate. If body fat percentage is known, the Katch–McArdle Formula may provide a more personalized estimate.
How many calories should I cut to lose weight?
A daily calorie deficit of approximately 500 calories may result in a weight loss of about 0.5 kg (1 pound) per week.
How many calories should I add to gain weight?
A calorie surplus of 250–500 calories per day is commonly recommended for gradual and sustainable weight gain.
Can calorie calculators be 100% accurate?
No. Calorie calculators provide estimates based on population averages. Actual calorie needs vary due to genetics, metabolism, hormones, body composition, and lifestyle factors.
What is a healthy rate of weight loss?
Most health professionals recommend losing approximately 0.25–1 kilogram (0.5–2 pounds) per week through a combination of calorie control and regular physical activity.
Factors That Affect Daily Calorie Needs
- Age
- Gender
- Height
- Weight
- Activity Level
- Body Composition
- Muscle Mass
- Health Conditions
Daily calorie requirements vary significantly from person to person. These factors influence how much energy your body burns each day.
How to Use the Calorie Calculator
- Select Metric or US units.
- Enter your age, gender, height, and weight.
- Choose an activity level.
- Select a BMR formula.
- Click Calculate.
- Review your maintenance, weight loss, and weight gain calorie targets.
This calculator is part of our Health Calculators collection.