Calorie Calculator — Daily Calorie Intake
Calculate how many calories you need per day to maintain, lose, or gain weight using the Mifflin-St Jeor equation. See also BMI Calculator and TDEE Calculator.
How Daily Calorie Needs Are Calculated
Step 1: Your Details
Age
Gender
Weight
Height
Step 2: Basal Metabolic Rate (BMR)
Calories your body burns at rest
Men: (10 × kg) + (6.25 × cm) − (5 × age) + 5
Women: (10 × kg) + (6.25 × cm) − (5 × age) − 161
Step 3: Total Daily Energy Expenditure (TDEE)
Your daily calorie needs to maintain current weight
Lose Weight
TDEE − 500
Maintain
= TDEE
Gain Weight
TDEE + 500
How the Calorie Calculator Works
This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate formula for estimating daily calorie needs by the American Dietetic Association. It first calculates your Basal Metabolic Rate (BMR) — the number of calories your body burns at complete rest to maintain basic functions like breathing, circulation, and cell production. Then it multiplies BMR by an activity factor to estimate your Total Daily Energy Expenditure (TDEE) — the total calories you burn in a day including physical activity.
Calorie Calculation Formula (Mifflin-St Jeor)
For Men:
For Women:
TDEE:
Example (25-year-old male, 70kg, 175cm, moderately active)
BMR = (10 × 70) + (6.25 × 175) − (5 × 25) + 5
BMR = 700 + 1093.75 − 125 + 5 = 1,673.75 cal/day
TDEE = 1,674 × 1.55 = 2,594 cal/day
Activity Level Multipliers
| Level | Multiplier | 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 |
| Very Active | 1.725 | Hard exercise 6-7 days/week |
| Extra Active | 1.9 | Very hard exercise, physical job |
Weight Loss and Weight Gain
To lose weight, you need to create a calorie deficit — consuming fewer calories than your TDEE. A deficit of 500 calories per day results in approximately 0.5 kg (1 lb) of weight loss per week, since 1 kg of body fat contains roughly 7,700 calories. To gain weight, create a calorie surplus by eating more than your TDEE.
Important: The minimum recommended daily intake is approximately 1,500 calories for men and 1,200 calories for women. Going below these levels without medical supervision can lead to nutritional deficiencies and metabolic slowdown.
Understanding Macronutrients
Macronutrients provide the energy (calories) your body needs. Protein (4 cal/gram) builds and repairs muscle tissue — aim for 0.8-1.2g per kg of body weight. Carbohydrates (4 cal/gram) are the body's primary energy source — whole grains, fruits, and vegetables are preferred. Fat (9 cal/gram) supports hormone production and nutrient absorption — focus on unsaturated fats from nuts, avocados, and olive oil. This calculator suggests a balanced 30/40/30 split (protein/carbs/fat), but optimal ratios vary by individual goals.
Frequently Asked Questions
How accurate is this calorie calculator?
The Mifflin-St Jeor equation is accurate to within 10% for most people. Individual variation depends on genetics, body composition, hormones, and metabolic adaptation. Use the result as a starting point and adjust based on real-world results over 2-4 weeks.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the calories burned at complete rest — just to keep your body alive. TDEE (Total Daily Energy Expenditure) includes BMR plus all physical activity. TDEE is always higher than BMR.
How many calories should I eat to lose weight?
A moderate deficit of 500 calories below your TDEE is recommended for sustainable weight loss of about 0.5 kg per week. Extreme deficits (over 1,000 cal) can cause muscle loss, nutritional deficiencies, and metabolic slowdown.
Why does the Mifflin-St Jeor equation differ for men and women?
Men typically have more lean muscle mass and less body fat than women at the same weight, which results in a higher metabolic rate. The +5 (men) vs -161 (women) constant accounts for this average difference in body composition.
Solved Examples
Example 1: Daily Calories for a Sedentary 30-Year-Old Woman (60 kg, 165 cm)
Solution:
Step 1: BMR = (10 × 60) + (6.25 × 165) − (5 × 30) − 161
Step 2: BMR = 600 + 1031.25 − 150 − 161 = 1,320 cal/day
Step 3: TDEE = BMR × Activity Factor = 1,320 × 1.2 (sedentary) = 1,584 cal/day
Step 4: To lose 0.5 kg/week: 1,584 − 500 = 1,084 cal/day (below minimum, use 1,200)
Answer: Maintenance = 1,584 cal/day. Safe weight loss target = 1,200 cal/day minimum.
Example 2: TDEE for an Active 25-Year-Old Man (80 kg, 180 cm, exercises 5 days/week)
Solution:
Step 1: BMR = (10 × 80) + (6.25 × 180) − (5 × 25) + 5
Step 2: BMR = 800 + 1125 − 125 + 5 = 1,805 cal/day
Step 3: TDEE = 1,805 × 1.55 (moderately active) = 2,798 cal/day
Step 4: To gain 0.5 kg/week: 2,798 + 500 = 3,298 cal/day
Answer: Maintenance = 2,798 cal/day. Bulking target = 3,298 cal/day.
Example 3: Calorie Deficit for Weight Loss (Male, 90 kg, 175 cm, 35 years, lightly active)
Solution:
Step 1: BMR = (10 × 90) + (6.25 × 175) − (5 × 35) + 5 = 900 + 1093.75 − 175 + 5 = 1,824
Step 2: TDEE = 1,824 × 1.375 = 2,508 cal/day
Step 3: Deficit for 1 kg/week loss: 2,508 − 1000 = 1,508 cal/day (above minimum, safe)
Step 4: Macros at 1,508 cal: Protein = 113g, Carbs = 151g, Fat = 50g
Answer: Eat 1,508 cal/day to lose approximately 1 kg per week.
Practice Questions
Q1: A 40-year-old sedentary woman weighs 75 kg and is 162 cm tall. What is her daily calorie need?
Answer: BMR = (10×75)+(6.25×162)−(5×40)−161 = 750+1012.5−200−161 = 1,402. TDEE = 1,402 × 1.2 = 1,682 cal/day.
Q2: How many calories should a very active 22-year-old male (70 kg, 178 cm) eat to maintain weight?
Answer: BMR = (10×70)+(6.25×178)−(5×22)+5 = 700+1112.5−110+5 = 1,708. TDEE = 1,708 × 1.725 = 2,946 cal/day.
Q3: If someone's TDEE is 2,200 cal and they eat 1,700 cal daily, how much weight will they lose in 4 weeks?
Answer: Daily deficit = 500 cal. Weekly deficit = 3,500 cal ≈ 0.45 kg. In 4 weeks: 0.45 × 4 = 1.8 kg (approximately 4 lbs).
Q4: A person has a BMR of 1,600. They exercise moderately. How many grams of protein should they eat daily for maintenance?
Answer: TDEE = 1,600 × 1.55 = 2,480 cal. Protein at 30% = 744 cal ÷ 4 cal/g = 186 grams of protein per day.
Q5: Why does a 50-year-old need fewer calories than a 25-year-old with the same stats?
Answer: The formula subtracts (5 × age). Difference = 5 × (50−25) = 125 fewer BMR calories, meaning about 194 fewer TDEE calories at moderate activity (125 × 1.55).
Q6: A person switches from sedentary (1.2) to moderately active (1.55). Their BMR is 1,500. How many more calories do they burn?
Answer: Sedentary TDEE = 1,500 × 1.2 = 1,800. Active TDEE = 1,500 × 1.55 = 2,325. Difference = 525 extra calories burned per day.
Common Mistakes to Avoid
The biggest mistake people make with calorie calculators is overestimating their activity level — selecting "Very Active" when they actually exercise 2-3 times per week inflates TDEE by 300-500 calories and prevents weight loss. Another common error is not accounting for NEAT (Non-Exercise Activity Thermogenesis), which includes fidgeting, walking to the car, and household chores — this can vary by 200-900 calories between individuals. People also forget to recalculate as they lose weight: a person who loses 10 kg has a lower BMR and needs fewer calories to maintain their new weight. Using the wrong unit system (entering weight in pounds but selecting the metric formula) produces wildly incorrect results. Finally, many people create dangerously aggressive deficits (1,000+ calories below TDEE) that lead to muscle loss, nutrient deficiency, and metabolic adaptation — a moderate 500-calorie deficit is safer and more sustainable long-term.
Key Takeaways
- The Mifflin-St Jeor equation is the gold standard for estimating calorie needs, accurate to within 10% for most people.
- TDEE = BMR × Activity Multiplier. A 500-calorie daily deficit produces about 0.5 kg (1 lb) of weight loss per week.
- Never eat below 1,500 cal/day (men) or 1,200 cal/day (women) without medical supervision.
- Recalculate your calorie needs after every 5-10 kg of weight change — your BMR decreases as you lose weight.
- Activity level selection has a massive impact: the difference between sedentary and very active is 700+ calories for most people.
- Macronutrients matter: protein (4 cal/g) preserves muscle during deficit, fat (9 cal/g) supports hormones, carbs (4 cal/g) fuel exercise.