Daily Calorie Needs Calculator

Follow these steps to calculate your daily calorie needs:

1. Enter your age in years. The calculator uses age because metabolic rate decreases by roughly 1-2% per decade after your mid-twenties.
2. Select your biological sex (male or female). The Mifflin-St Jeor formula uses different constants for men and women to account for differences in body composition.
3. Enter your weight in pounds. Your body weight directly influences how many calories you burn at rest, as larger bodies require more energy to maintain.
4. Enter your total height in inches. To convert feet and inches, multiply feet by 12 and add the remaining inches (for example, 5 feet 9 inches equals 69 inches).
5. Select your activity level honestly. This is the most common source of error. Be realistic about your average week rather than your best week. If you exercise three days but sit at a desk the other four, moderately active is likely the right choice.

After clicking calculate, the tool displays four key results: your BMR (calories at rest), maintenance calories (calories to stay at your current weight), a weight loss target (500-calorie deficit for roughly one pound of loss per week), and a weight gain target (500-calorie surplus for roughly one pound of gain per week). Use maintenance calories as your baseline and adjust up or down depending on your goal. Track your weight over two to four weeks and adjust by 100 to 200 calories if progress stalls.

A calorie calculator estimates the number of calories your body needs each day to maintain, lose, or gain weight. Calories are units of energy that your body derives from the food and beverages you consume. Every physiological process, from breathing and circulating blood to thinking and exercising, requires energy measured in calories. The total number of calories you burn in a day is known as your Total Daily Energy Expenditure (TDEE), which is built on top of your Basal Metabolic Rate (BMR), the energy your body requires at complete rest just to sustain vital organ functions.

Calorie needs vary significantly from person to person based on five primary factors: age, biological sex, body weight, height, and physical activity level. As you age, your metabolism naturally slows, reducing your calorie needs. Men generally require more calories than women due to greater muscle mass and larger body size. Heavier and taller individuals burn more energy simply because there is more tissue to maintain. Finally, someone who exercises intensely every day will burn far more calories than a sedentary office worker.

This calculator uses the Mifflin-St Jeor equation, published in 1990 and widely regarded as the gold standard for estimating BMR. Research has shown it to be more accurate than the older Harris-Benedict equation, which was originally developed in 1919 and revised in 1984. While the Harris-Benedict formula tends to overestimate calorie needs by roughly 5%, the Mifflin-St Jeor equation provides predictions within approximately 10% of measured values for the majority of healthy adults. Understanding your calorie needs is a foundational step in any weight management plan, whether your goal is fat loss, muscle gain, or simply maintaining your current physique.

This calculator uses the Mifflin-St Jeor equation to estimate Basal Metabolic Rate (BMR):

• Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
• Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

Once BMR is calculated, it is multiplied by an activity factor to determine your Total Daily Energy Expenditure (TDEE), also called maintenance calories:

Maintenance Calories = BMR × Activity Multiplier

Variable definitions:

Example 1 — Sedentary Office Worker: A 35-year-old female weighing 150 lbs (68.0 kg) and 5'5" (165.1 cm) tall with a sedentary lifestyle. BMR = 10(68.0) + 6.25(165.1) − 5(35) − 161 = 680 + 1,031.9 − 175 − 161 = 1,375.9 cal. Maintenance = 1,376 × 1.2 = 1,651 cal/day. Weight loss target = 1,651 − 500 = 1,151 cal/day. Because this falls below the recommended 1,200-calorie minimum for women, she should aim for 1,200 calories and accept slower weight loss, or increase her activity level.

Example 2 — Active Athlete: A 28-year-old male weighing 190 lbs (86.2 kg) and 6'1" (185.4 cm) tall who trains hard six days a week. BMR = 10(86.2) + 6.25(185.4) − 5(28) + 5 = 862 + 1,158.8 − 140 + 5 = 1,885.8 cal. Maintenance = 1,886 × 1.725 = 3,253 cal/day. This athlete needs over 3,200 calories just to maintain his weight, and would target approximately 3,750 calories to support a lean bulk of one pound per week.

Example 3 — Weight Loss Scenario: A 42-year-old male weighing 220 lbs (99.8 kg) and 5'10" (177.8 cm) tall with light activity. BMR = 10(99.8) + 6.25(177.8) − 5(42) + 5 = 998 + 1,111.3 − 210 + 5 = 1,904.3 cal. Maintenance = 1,904 × 1.375 = 2,618 cal/day. Weight loss target = 2,618 − 500 = 2,118 cal/day. At this deficit, he can expect to lose about one pound per week. After losing 15 to 20 pounds, he should recalculate because his lower body weight will reduce his BMR and maintenance needs.