Calorie Calculator
Estimate how many calories you need per day to maintain, lose, or gain weight. Uses the Mifflin-St Jeor equation, widely considered the most accurate formula for calculating resting metabolic rate.
Maintenance
2,633 cal/day
Mild Weight Loss (-250 cal)
2,383 cal/day
Weight Loss (-500 cal)
2,133 cal/day
Weight Gain (+500 cal)
3,133 cal/day
How to use
Enter your age, select your gender, input your height and weight, and choose your activity level from sedentary to extra active. The calculator determines your Basal Metabolic Rate (BMR) and multiplies it by your activity factor to estimate daily calories for maintenance. It also shows targets for mild weight loss (-250 cal), weight loss (-500 cal), and weight gain (+500 cal).
Mifflin-St Jeor Formula
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161 + 166
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161
The BMR is then multiplied by an activity factor: Sedentary (×1.2), Lightly Active (×1.375), Moderately Active (×1.55), Very Active (×1.725), or Extra Active (×1.9). This gives your Total Daily Energy Expenditure (TDEE), the number of calories you burn per day.
When this calculator helps
Whether you want to lose weight, gain muscle, or simply maintain your current physique, knowing your daily calorie needs is the foundation of any nutrition plan. This calculator is used by dietitians, personal trainers, and individuals managing their health. Instead of following generic advice like "eat 2,000 calories a day," you get a personalized estimate based on your unique body metrics and lifestyle. It takes the guesswork out of meal planning and helps you set realistic, achievable calorie targets for your specific goals.
Examples
Example 1: Sedentary Office Worker
A 35-year-old woman, 5'5", 140 lbs, with a desk job and no regular exercise. Her BMR is approximately 1,370 calories. With a sedentary activity multiplier of 1.2, her TDEE is about 1,645 calories. To lose 1 lb/week, she would target roughly 1,145 calories daily.
Example 2: Active College Student
A 22-year-old man, 5'11", 175 lbs, who works out 4-5 times per week. His BMR is about 1,815 calories. With a "very active" multiplier of 1.725, his TDEE is approximately 3,130 calories. To maintain his weight while training, he needs to eat around 3,100 calories per day.
Example 3: Person Looking to Gain Weight
A 28-year-old man, 5'8", 145 lbs, lightly active. His BMR is about 1,620 calories, and TDEE is approximately 2,230. To gain 1 lb/week, he should eat around 2,730 calories daily. Adding a protein shake and an extra meal would cover this 500-calorie surplus.
Things to watch
- •Be honest about your activity level, most people overestimate. If you exercise 3 times a week but sit the rest of the day, choose "lightly active" rather than "moderately active."
- •Your TDEE is an estimate, not an exact number. Track your weight for 2-3 weeks and adjust calories up or down based on actual results.
- •Calorie quality matters as much as quantity, 2,000 calories of whole foods will fuel your body differently than 2,000 calories of processed snacks.
- •Recalculate your TDEE after every 10-15 lbs of weight change, as your BMR decreases as you lose weight and increases as you gain.
- •Do not drop calories too aggressively. Extreme restriction slows your metabolism and often leads to rebound weight gain.
Sources and methodology
Last reviewed: April 25, 2026. We review formulas, default assumptions, and examples against public references when a formal source applies.
Method: This calculator uses the formula explained on this page, then checks default assumptions and examples against the references listed below.
- •Dietary Guidelines for Americans, 2020-2025, U.S. Department of Health and Human Services
- •Body Weight Planner, National Institutes of Health
Found something off? Send a correction with the page URL, inputs, result, and expected result.
Common questions
- How many calories should I eat per day?
- Daily calorie needs vary based on age, sex, height, weight, and activity level. On average, women need about 1,600-2,400 calories and men need about 2,000-3,000 calories per day. Use our calculator to find your specific Total Daily Energy Expenditure (TDEE).
- What is TDEE?
- TDEE (Total Daily Energy Expenditure) is the total number of calories you burn each day, including your basal metabolic rate plus calories burned through activity and exercise. It's calculated by multiplying your BMR by an activity factor ranging from 1.2 (sedentary) to 1.9 (extremely active).
- How many calories should I cut to lose weight safely?
- A deficit of 500 calories per day leads to approximately 1 pound of weight loss per week, which is considered safe and sustainable. Cutting more than 1,000 calories daily is generally not recommended as it can lead to muscle loss, nutrient deficiencies, and metabolic slowdown. Never go below 1,200 calories (women) or 1,500 calories (men) without medical supervision.
- Does exercise change how many calories I need?
- Yes, a lot. A sedentary person might need 1,800 calories while someone with the same stats who exercises intensely 6 days a week could need 2,800 or more. The activity multiplier in the Mifflin-St Jeor equation accounts for this, but remember that people often overestimate exercise intensity and underestimate food intake.
- Why is the Mifflin-St Jeor formula considered the most accurate?
- Published in 1990, the Mifflin-St Jeor equation was validated against indirect calorimetry (the gold standard for measuring metabolic rate). Studies show it predicts BMR within 10% for most healthy adults, outperforming older equations like Harris-Benedict. It works well across a wide range of body weights and ages.