Question 1

What is BMR and how is it calculated?

Accepted Answer

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to sustain vital functions — breathing, circulation, and cell repair. This calculator uses the Mifflin-St Jeor equation: 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.

Question 2

What is TDEE and why does it matter?

Accepted Answer

TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor. It represents the total calories you burn per day including exercise and daily movement. TDEE is the number you use for weight management: eating below TDEE causes weight loss, above causes weight gain, and at TDEE maintains your current weight.

Question 3

How many calories should I eat to lose weight?

Accepted Answer

A safe calorie deficit for weight loss is 500 calories per day below your TDEE, which results in approximately 0.5 kg (1 lb) of fat loss per week. Avoid dropping below 1,200 calories/day for women or 1,500 calories/day for men without medical supervision, as this can reduce muscle mass and slow metabolism.

Question 4

How many calories do I need to build muscle?

Accepted Answer

To build muscle (bulk), aim for a caloric surplus of 250–500 calories above your TDEE. Pair this with adequate protein intake (1.6–2.2 g per kg of body weight) and progressive resistance training. A modest surplus minimizes fat gain while supporting muscle growth.

Question 5

What activity level should I choose?

Accepted Answer

Sedentary: desk job, little or no exercise. Lightly active: light exercise 1–3 days/week. Moderately active: moderate exercise 3–5 days/week. Very active: hard exercise 6–7 days/week. Extremely active: physical job plus intense daily training. Most people overestimate their activity level — if unsure, choose one level below what feels right.

Question 6

How accurate is the Mifflin-St Jeor equation?

Accepted Answer

The Mifflin-St Jeor equation is the most widely validated formula in clinical nutrition research and is used by dietitians worldwide. Studies show it estimates BMR within 10% accuracy for most people. It is more accurate than the older Harris-Benedict equation. Athletes or people with very high or low body fat percentages may see larger variations.

Question 7

Does age affect calorie needs?

Accepted Answer

Yes. Calorie needs generally decrease with age due to declining muscle mass (sarcopenia) and reduced metabolic rate. After age 30, BMR typically drops about 1–2% per decade. Maintaining muscle mass through resistance training can significantly offset this decline and keep your metabolic rate higher as you age.

Question 8

Do men and women need different calorie amounts?

Accepted Answer

Yes. Men generally have higher calorie needs than women of the same height, weight, and age, primarily because men have more muscle mass, which burns more calories at rest. On average, men need 2,000–2,500 kcal/day and women need 1,600–2,000 kcal/day for maintenance, though this varies widely by body composition and activity.

Question 9

How do I calculate calories for weight maintenance?

Accepted Answer

Your maintenance calories equal your TDEE. Calculate it using this tool by selecting 'maintain weight' as your goal. Eat this number of calories daily and your weight should remain stable over time. Weigh yourself weekly at the same time to track your actual maintenance level, as calculators provide estimates.

Question 10

Is my health data stored when using this calculator?

Accepted Answer

No. All calculations happen locally in your browser. We do not collect, store, or transmit any personal information you enter — your age, weight, height, and goals remain entirely private on your device.

Calorie Calculator

Calorie Formula (Mifflin-St Jeor)

Calorie Calculator — FAQs

How to Use This Calculator

Step 1: Enter Personal Info

Step 2: Select Activity Level

Step 3: Choose Your Goal

Step 4: Get Your Results