Calorie Calculator - Free Online Tool

Calculate your daily calorie needs for weight loss, maintenance, or weight gain

Welcome to our free Calorie Calculator, a science-based tool that estimates your daily caloric needs using the Mifflin-St Jeor equation - widely recognized as the most accurate formula for calculating Basal Metabolic Rate (BMR). Whether you're trying to lose weight, maintain your current weight, or gain muscle, knowing your calorie needs is the first step. Your body burns calories throughout the day just to stay alive - this is your Basal Metabolic Rate (BMR). Activities like walking, exercising, and even digesting food increase your total daily energy expenditure (TDEE). Our calculator factors in your age, gender, height, weight, and activity level to give you a personalized calorie target. The calculator provides calorie targets for different goals: mild weight loss (0.5 lb/week), moderate weight loss (1 lb/week), extreme weight loss (2 lb/week), as well as weight gain targets. It also includes a balanced macro breakdown showing recommended protein, carbohydrate, and fat intake in grams. Understanding your calorie needs helps you make informed nutrition decisions. A calorie deficit (eating fewer calories than you burn) leads to weight loss, while a calorie surplus leads to weight gain. The key is finding a sustainable approach that aligns with your health goals. Our calculator uses both imperial (pounds, feet/inches) and metric (kilograms, centimeters) units. All calculations are performed instantly in your browser with complete privacy - no data is stored or sent to any server. Remember that calorie calculators provide estimates based on population averages. Individual metabolism varies based on genetics, muscle mass, hormones, and other factors. Use these numbers as a starting point and adjust based on your actual results over 2-4 weeks.

Understanding Calorie Calculation

Calorie calculations use scientifically validated formulas to estimate your daily energy needs based on personal characteristics and activity level.

The Mifflin-St Jeor Equation

Our calculator uses the Mifflin-St Jeor equation, developed in 1990 and considered the most accurate BMR formula. For men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161.

Activity Multipliers

Your BMR is multiplied by an activity factor to estimate total daily calories: Sedentary (×1.2), Light exercise (×1.375), Moderate exercise (×1.55), Active (×1.725), Very active (×1.9). Choose the level that best matches your typical week.

Formulas

Mifflin-St Jeor (Men)

BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5

The most accurate BMR equation for the general population, recommended by the American Dietetic Association.

Mifflin-St Jeor (Women)

BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Female version with a gender-specific constant of −161 to account for lower average metabolic rate.

TDEE (Total Daily Energy Expenditure)

TDEE = BMR × Activity Factor

Multiply BMR by an activity multiplier (1.2 to 1.9) to estimate total calories burned per day including exercise and daily movement.

Calorie Deficit for Weight Loss

Daily Calories = TDEE − (Weekly Goal lbs × 500)

Each pound of fat equals approximately 3,500 calories. A 500 cal/day deficit produces about 1 lb/week weight loss.

Reference Tables

Activity Level Multipliers

Multiply your BMR by the corresponding factor to estimate your total daily energy expenditure

Activity Level	Factor	Description
Sedentary	1.2	Little or no exercise, desk job
Lightly Active	1.375	Light exercise 1–3 days/week
Moderately Active	1.55	Moderate exercise 3–5 days/week
Active	1.725	Hard exercise 6–7 days/week
Very Active	1.9	Very hard daily exercise or physical job

Macronutrient Calorie Values

Energy content per gram of each macronutrient, used to convert calorie targets into grams

Macronutrient	Calories per Gram	Typical % of Diet
Protein	4 cal/g	25–35%
Carbohydrates	4 cal/g	35–55%
Fat	9 cal/g	20–35%
Alcohol	7 cal/g	N/A

Worked Examples

Example 1: Maintenance Calories for a Sedentary Adult

A 35-year-old male, weight 85 kg (187 lbs), height 180 cm (5'11"), sedentary lifestyle.

BMR = 10 × 85 + 6.25 × 180 − 5 × 35 + 5

BMR = 850 + 1,125 − 175 + 5 = 1,805 cal/day

TDEE = BMR × 1.2 (sedentary) = 1,805 × 1.2 = 2,166 cal/day

Maintenance calories are approximately 2,166 cal/day. Eating this amount will maintain current weight.

Example 2: Calorie Target for Weight Loss

A 28-year-old female, weight 70 kg (154 lbs), height 165 cm (5'5"), moderately active, goal: lose 1 lb/week.

BMR = 10 × 70 + 6.25 × 165 − 5 × 28 − 161

BMR = 700 + 1,031.25 − 140 − 161 = 1,430 cal/day

TDEE = BMR × 1.55 (moderately active) = 1,430 × 1.55 = 2,217 cal/day

Weight loss target = TDEE − 500 = 2,217 − 500 = 1,717 cal/day

Macro split (30/40/30): Protein = 129g, Carbs = 172g, Fat = 57g

To lose 1 lb/week, eat approximately 1,717 cal/day with 129g protein, 172g carbs, and 57g fat.

How to Use the Calorie Calculator

Enter Your Details

Select your gender and enter your age. These affect your basal metabolic rate, which is the calories your body burns at rest.

Enter Height & Weight

Choose imperial or metric units, then enter your current weight and height. These are the primary factors in calculating your BMR.

Select Activity Level

Choose the activity level that best describes your typical week. Be honest - overestimating activity leads to eating too many calories.

Review Your Calorie Targets

See your maintenance calories, weight loss/gain targets, and suggested macro breakdown. Adjust your diet based on your specific goal.

Frequently Asked Questions

How many calories should I eat per day to lose weight?

To lose weight, you need to eat fewer calories than your body burns (calorie deficit). A safe and sustainable rate is 1-2 pounds per week, which requires a daily deficit of 500-1,000 calories below your maintenance level. For example, if your maintenance calories are 2,500, eating 2,000 calories daily would result in about 1 pound of weight loss per week. Never go below 1,500 calories for men or 1,200 for women without medical supervision, as very low calorie diets can cause nutrient deficiencies and metabolic slowdown.

What is BMR and why does it matter?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to maintain basic life functions like breathing, circulation, and cell production. It typically accounts for 60-75% of your total daily calorie burn. Knowing your BMR helps you understand your body's minimum energy needs. Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. Our calculator uses the Mifflin-St Jeor equation, which is the most accurate BMR formula according to the American Dietetic Association.

Which activity level should I choose?

Be honest and slightly conservative when choosing your activity level. Sedentary: Office worker with no regular exercise. Lightly Active: Walking 30 minutes daily or light exercise 1-3 times per week. Moderately Active: Exercise at moderate intensity 3-5 times per week for 30-60 minutes. Active: Intense exercise 6-7 days per week or a physically demanding job. Very Active: Intense daily exercise plus a physically demanding job, or training twice daily. Most people overestimate their activity level. If in doubt, choose one level lower and adjust based on results.

How accurate is this calorie calculator?

The Mifflin-St Jeor equation used by our calculator is the most accurate predictive equation for BMR, with an accuracy of about 80-90% for most people. However, individual metabolism varies based on genetics, muscle mass, hormone levels, and other factors. Use the calculated values as a starting point, then track your weight for 2-4 weeks. If you're not seeing expected results, adjust by 100-200 calories. Factors like stress, sleep quality, medications, and medical conditions can also affect your actual calorie needs.

What are macros and how should I split them?

Macros (macronutrients) are the three main nutrient groups: protein, carbohydrates, and fat. Our calculator suggests a balanced 30/40/30 split. Protein (30%): Essential for muscle repair and satiety. Each gram provides 4 calories. Good sources include chicken, fish, eggs, and legumes. Carbohydrates (40%): Your body's primary energy source. Each gram provides 4 calories. Choose whole grains, fruits, and vegetables. Fat (30%): Important for hormone production and nutrient absorption. Each gram provides 9 calories. Focus on healthy fats from nuts, avocados, and olive oil.