Calorie Calculator
Estimate your daily calorie needs using BMR formulas and activity level. Enter your details below to get your maintenance, weight loss, and weight gain targets.
| Basal Metabolic Rate (BMR) | --- |
| Activity Factor | --- |
| Weight Loss (-250 cal/day) | --- |
| Weight Loss (-500 cal/day) ~1 lb/week | --- |
| Weight Loss (-1000 cal/day) ~2 lb/week | --- |
| Weight Gain (+250 cal/day) | --- |
| Weight Gain (+500 cal/day) | --- |
What Are Calories?
A calorie is a unit of energy. In nutrition, a calorie (or kilocalorie) represents the amount of energy needed to raise the temperature of 1 kilogram of water by 1 degree Celsius. Your body uses calories from food and drink to fuel every function — from breathing and circulating blood to exercising and digesting food. Understanding your calorie needs is fundamental to managing your weight, whether your goal is maintenance, weight loss, or weight gain.
Three macronutrients provide calories: carbohydrates and protein provide 4 calories per gram, while fat provides 9 calories per gram. Alcohol provides 7 calories per gram but offers no nutritional value.
Who Is This Calculator For?
This calorie calculator is designed for adults (ages 15-80) who want to estimate their daily energy needs. It is useful for anyone managing their weight — whether you want to lose, gain, or maintain. Athletes, fitness enthusiasts, people starting a new diet plan, and healthcare professionals can all benefit from understanding BMR and TDEE. The calculator offers three different BMR formulas so you can compare results.
BMR vs. TDEE: The Foundation of Calorie Planning
Basal Metabolic Rate (BMR) is the number of calories your body needs at complete rest to maintain vital functions — breathing, circulation, cell production, and brain function. BMR accounts for approximately 60-75% of your total daily calorie expenditure and is primarily determined by your lean body mass, age, gender, and genetics.
Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day. It is calculated by multiplying your BMR by an activity factor that accounts for all physical activity — from walking and household chores to dedicated exercise. TDEE = BMR × Activity Factor.
To manage your weight, compare your calorie intake to your TDEE: eat at TDEE to maintain, below TDEE to lose weight, and above TDEE to gain weight.
BMR Formulas Used in This Calculator
This calculator supports three widely validated BMR equations. You can switch between them to compare results.
1. Mifflin-St Jeor Equation (Recommended)
Developed in 1990, this is currently considered the most accurate BMR formula for the general population:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) - 161
Example: A 30-year-old man weighing 80 kg and 180 cm tall has a BMR of 10(80) + 6.25(180) - 5(30) + 5 = 800 + 1125 - 150 + 5 = 1,780 calories/day.
2. Revised Harris-Benedict Equation
Originally developed in 1919 and revised in 1984, this was the gold standard for decades:
Men: BMR = 13.397 × weight(kg) + 4.799 × height(cm) - 5.677 × age(y) + 88.362
Women: BMR = 9.247 × weight(kg) + 3.098 × height(cm) - 4.330 × age(y) + 447.593
This equation tends to slightly overestimate BMR compared to Mifflin-St Jeor, particularly in overweight individuals.
3. Katch-McArdle Formula
This formula uses lean body mass rather than total weight, making it the most accurate for individuals who know their body fat percentage:
BMR = 370 + 21.6 × (1 - body fat fraction) × weight(kg)
Where body fat fraction = body fat percentage / 100. For example, a person weighing 70 kg with 20% body fat has a lean mass of 70 × (1 - 0.20) = 56 kg, and a BMR of 370 + 21.6 × 56 = 1,580 calories/day.
This formula is particularly useful for athletes and lean individuals. Use our Body Fat Calculator to estimate your body fat percentage first. Once you know your calorie targets, our Macros Calculator can help you break those calories into the right protein, carb, and fat ratios.
How to Use This Calculator
- Choose your unit system — Metric (kg/cm) or US (lbs/ft/in).
- Select your gender — BMR formulas differ for men and women.
- Enter your age, weight, and height.
- Select your activity level — Be honest about your typical daily activity (see table below).
- Choose a BMR formula — Mifflin-St Jeor (recommended), Harris-Benedict, or Katch-McArdle.
- If using Katch-McArdle, enter your body fat percentage.
- Click "Calculate" — Your BMR, TDEE, and calorie targets for weight loss and gain will be displayed.
Activity Level Table
| Level | Factor | Description |
|---|---|---|
| BMR | 1.0 | Complete rest — not used for daily estimates |
| Sedentary | 1.2 | Little or no exercise, desk job, mostly sitting |
| Light | 1.375 | Light exercise 1-3 days per week |
| Moderate | 1.465 | Moderate exercise 4-5 days per week |
| Active | 1.55 | Daily exercise or intense exercise 3-4 days per week |
| Very Active | 1.725 | Intense exercise 6-7 days per week |
| Extra Active | 1.9 | Very intense daily exercise or physically demanding job |
Choose the activity level that best describes your typical week, not your best week. Overestimating activity level is one of the most common mistakes in calorie planning.
Calorie Deficit and Surplus for Weight Change
One pound of body fat equals approximately 3,500 calories. To change your weight, you need to create a consistent calorie deficit (to lose) or surplus (to gain):
| Goal | Daily Adjustment | Weekly Rate |
|---|---|---|
| Maintenance | TDEE | No change |
| Mild weight loss | TDEE - 250 cal | ~0.5 lb (0.23 kg) |
| Moderate weight loss | TDEE - 500 cal | ~1 lb (0.45 kg) |
| Aggressive weight loss* | TDEE - 1000 cal | ~2 lb (0.9 kg) |
| Mild weight gain | TDEE + 250 cal | ~0.5 lb (0.23 kg) |
| Moderate weight gain | TDEE + 500 cal | ~1 lb (0.45 kg) |
*Aggressive weight loss should only be undertaken with medical supervision.
Safe Weight Loss Guidelines
- Gradual is sustainable: Aim for 0.5-1 lb (0.23-0.45 kg) per week. Faster rates often lead to muscle loss and metabolic adaptation.
- Minimum calorie floors: Women should not consume fewer than 1,200 calories/day and men should not go below 1,500 calories/day without medical supervision.
- Preserve muscle: Consume adequate protein (1.6-2.2 g per kg of body weight) and continue strength training during a deficit.
- Don't cut too much: A deficit larger than 1,000 calories/day can slow metabolism, cause nutrient deficiencies, and lead to muscle loss.
- Consider reverse dieting: After extended calorie restriction, gradually increase calories to restore metabolic rate before cutting again.
Maintenance, Cutting, and Bulking
In the fitness and nutrition world, different calorie phases are used for different goals:
- Maintenance phase: Eating at TDEE. Ideal for sustaining current weight while allowing flexibility in diet. Useful during breaks between cutting and bulking cycles.
- Cutting (weight loss) phase: Eating 300-500 calories below TDEE. The goal is to lose body fat while preserving as much muscle as possible. Typically lasts 8-16 weeks.
- Bulking (weight gain) phase: Eating 250-500 calories above TDEE. The goal is to build muscle mass. A "clean bulk" emphasizes nutrient-dense foods, while a "dirty bulk" includes more processed foods for faster (but less lean) weight gain.
Most people cycle through these phases, spending more time in maintenance than in cutting or bulking.
FAQ
BMR (Basal Metabolic Rate) is the calories your body needs at complete rest just to survive — breathing, heart beat, cell repair. It accounts for 60-75% of your daily burn. TDEE (Total Daily Energy Expenditure) is BMR multiplied by your activity level, representing all calories burned in a day including exercise, walking, digestion, and fidgeting. TDEE is the number you should use for weight management.
The Mifflin-St Jeor Equation is widely considered the most accurate for the general population, with an error rate of about 10%. The Katch-McArdle Formula can be more accurate for lean individuals who know their body fat percentage because it uses lean body mass. The Harris-Benedict Equation is a historical standard but tends to overestimate by 5-10% compared to Mifflin-St Jeor. For most people, Mifflin-St Jeor is the recommended choice.
A common approach is to subtract 300-500 calories from your TDEE for gradual weight loss of 0.5-1 lb per week. For faster weight loss (under medical supervision), a deficit of up to 1,000 calories per day (2 lbs/week) may be appropriate. Women should generally not go below 1,200 calories and men should not go below 1,500 calories without professional guidance. The most important factor is consistency over time.
Since your activity factor in TDEE already accounts for your general exercise level, you generally do not need to eat back calories burned during exercise if your goal is weight loss. However, if you perform unusually intense or long workouts, you may need additional fuel for recovery and performance. Listen to your body — if you feel lethargic, irritable, or are not recovering well, consider adding 100-200 calories on training days.
Clean bulking involves eating 250-500 calories above TDEE from nutrient-dense foods — lean proteins, whole grains, fruits, vegetables, and healthy fats. This results in slower, leaner weight gain with minimal fat accumulation. Dirty bulking involves a larger surplus (500+ calories) with less emphasis on food quality, leading to faster weight gain but more fat gain. Clean bulking is generally recommended for those who want to minimize fat gain while building muscle.
Several factors could be at play: (1) You may be underestimating your calorie intake — food logs are often off by 20-50%. (2) Your activity level may be lower than you think — many people overestimate their NEAT (non-exercise activity thermogenesis). (3) Water retention can mask fat loss — scale weight fluctuates with sodium, carbohydrate intake, and hormonal changes. (4) Metabolic adaptation — prolonged deficits can lower your metabolic rate. (5) Medical conditions like hypothyroidism or PCOS. If progress stalls for more than 2-3 weeks, reassess your intake and activity honestly.
Free Online Calculators
Activity Level Factors
| Level | Factor |
|---|---|
| BMR | 1.0 |
| Sedentary | 1.2 |
| Light | 1.375 |
| Moderate | 1.465 |
| Active | 1.55 |
| Very Active | 1.725 |
| Extra Active | 1.9 |
Calorie Quick Facts
- 1 lb of body fat = 3,500 calories.
- A deficit of 500 cal/day = ~1 lb lost per week.
- Muscle burns more calories at rest than fat.
- Protein has 4 cal/g, carbs 4 cal/g, fat 9 cal/g.
- Alcohol has 7 cal/g — mostly empty calories.
- Drinking water can boost metabolism temporarily.
