How to Calculate Daily Calories for Your Goals

Knowing how many calories your body needs each day is the foundation of any weight management plan. Eat below that number consistently and you lose weight. Eat above it and you gain. The challenge is finding your actual number rather than relying on generic advice like “eat 2,000 calories a day.”

This guide covers the Mifflin-St Jeor equation (the most accurate formula widely available), activity multipliers, and how to adjust for specific goals. For quick results, use our Calorie Calculator or TDEE Calculator.

Medical Disclaimer: Calorie calculations provide estimates based on statistical averages. Individual metabolism varies based on genetics, medical conditions, medications, and other factors. Consult a registered dietitian or physician before starting any diet plan, especially if you have diabetes, eating disorders, thyroid conditions, or other health concerns.

Step 1: Calculate Your BMR

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to keep you alive. This covers breathing, circulation, cell production, and temperature regulation. BMR typically accounts for 60-75% of your total daily calorie expenditure.

The Mifflin-St Jeor equation, published in 1990 and validated in numerous studies since, is considered the most accurate predictive formula for most adults:

For men:

$BMR = (10 \times weight_{kg}) + (6.25 \times height_{cm}) - (5 \times age) + 5$

For women:

$BMR = (10 \times weight_{kg}) + (6.25 \times height_{cm}) - (5 \times age) - 161$

Worked Example (Male): A 35-year-old man, 180 cm tall, weighing 82 kg.

• Weight component: 10 x 82 = 820
• Height component: 6.25 x 180 = 1,125
• Age component: 5 x 35 = 175
• BMR = 820 + 1,125 - 175 + 5 = 1,775 calories/day

Worked Example (Female): A 28-year-old woman, 165 cm tall, weighing 64 kg.

• Weight component: 10 x 64 = 640
• Height component: 6.25 x 165 = 1,031
• Age component: 5 x 28 = 140
• BMR = 640 + 1,031 - 140 - 161 = 1,370 calories/day

Step 2: Apply Your Activity Multiplier

BMR tells you what your body burns at rest. To find your Total Daily Energy Expenditure (TDEE), multiply BMR by an activity factor that accounts for exercise, walking, standing, and general movement throughout the day.

Activity Level	Multiplier	Description
Sedentary	1.2	Desk job, little to no exercise
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
Extremely Active	1.9	Physical job + intense training

TDEE Formula:

$TDEE = BMR \times Activity \ Multiplier$

Continuing the male example: BMR of 1,775 with moderate exercise (3-5 days/week).

• TDEE = 1,775 x 1.55 = 2,751 calories/day

Continuing the female example: BMR of 1,370 with light exercise (1-3 days/week).

• TDEE = 1,370 x 1.375 = 1,884 calories/day

These TDEE values represent maintenance calories: the amount you need to eat to stay at your current weight.

Step 3: Adjust for Your Goal

Once you know your TDEE, adjust based on what you want to achieve.

Weight Loss

A calorie deficit means eating fewer calories than your TDEE. A deficit of 500 calories per day produces roughly 1 pound (0.45 kg) of weight loss per week, since one pound of body fat stores approximately 3,500 calories.

• Moderate deficit (recommended): TDEE minus 500 calories/day = ~1 lb/week loss
• Aggressive deficit: TDEE minus 750 calories/day = ~1.5 lbs/week loss
• Minimum safe intake: Generally 1,200 for women and 1,500 for men (consult a doctor for lower targets)

Example: Our male with a TDEE of 2,751 wants to lose weight at a moderate pace.

• Target intake: 2,751 - 500 = 2,251 calories/day

Weight Gain / Muscle Building

A calorie surplus means eating more than your TDEE. For lean muscle gain, a moderate surplus works best because excess calories beyond what muscles can use get stored as fat.

• Lean bulk: TDEE plus 250-350 calories/day
• Standard bulk: TDEE plus 500 calories/day

Example: Our female wants to build muscle and switches to moderate activity (TDEE of ~2,124).

• Target intake: 2,124 + 300 = 2,424 calories/day

Maintenance

Eat at your TDEE. This is also useful as a “diet break” strategy where you eat at maintenance for 1-2 weeks between deficit periods to reduce metabolic adaptation and psychological fatigue.

Macronutrient Basics

Total calories matter most for weight change, but how you divide those calories among protein, carbohydrates, and fat affects body composition, energy levels, and satiety.

Macronutrient	Calories per gram	General range
Protein	4	25-35% of total calories
Carbohydrates	4	35-50% of total calories
Fat	9	20-35% of total calories

Protein is the priority. Research consistently shows that higher protein intake (0.7-1.0 g per pound of body weight) preserves muscle during a deficit and supports muscle growth during a surplus. Protein also has the highest thermic effect of food, meaning your body burns more calories digesting it.

Worked Example: Our male eating 2,251 calories for weight loss at 82 kg (180 lbs).

• Protein target: 180 lbs x 0.8 g/lb = 144 g protein = 576 calories (26%)
• Fat target: 30% of 2,251 = 675 calories = 75 g fat
• Remaining carbs: 2,251 - 576 - 675 = 1,000 calories = 250 g carbs

Why TDEE Changes Over Time

Your calorie needs aren’t static. Several factors cause them to shift:

• Weight change: A lighter body burns fewer calories at rest. Recalculate after every 10-15 lbs of change.
• Age: BMR decreases roughly 1-2% per decade after age 20, primarily due to muscle loss.
• Metabolic adaptation: Extended dieting can reduce metabolic rate by 5-15% beyond what weight loss alone would predict. This is your body conserving energy.
• Muscle mass: Muscle tissue burns more calories at rest than fat tissue. Strength training helps maintain or increase BMR.
• Hormonal changes: Thyroid function, cortisol levels, menstrual cycles, and menopause all influence metabolic rate.

This is why periodic recalculation matters. A calorie target that produced steady weight loss three months ago may now be your new maintenance level.

Common Mistakes

Overestimating activity level: Most people with desk jobs who exercise 3 times a week are “lightly active,” not “moderately active.” When in doubt, pick the lower multiplier.

Ignoring liquid calories: Coffee drinks, juices, alcohol, and smoothies add up. A daily latte and evening glass of wine can account for 400+ calories that are easy to overlook.

Relying on exercise machine calorie displays: Treadmills and ellipticals routinely overestimate calories burned by 20-40%. Don’t eat back all the calories your fitness tracker reports.

Cutting too aggressively: Very low calorie diets (below 1,200) cause muscle loss, nutrient deficiencies, and metabolic slowdown. A moderate deficit sustained over months outperforms a crash diet every time.

Skip the Math

Our Calorie Calculator runs the Mifflin-St Jeor equation with your inputs and shows targets for loss, maintenance, and gain. Pair it with the TDEE Calculator for a detailed breakdown of your total daily energy expenditure across different activity scenarios.

Frequently Asked Questions

How accurate are calorie calculators?

Predictive equations like Mifflin-St Jeor are accurate within 10% for about 80% of the population. The remaining 20% may see larger deviations due to genetics, body composition extremes, or medical conditions. Treat calculator results as a starting point and adjust based on real-world results over 2-3 weeks. If you’re not losing or gaining as expected, shift your intake by 100-200 calories and reassess.

Should I eat back the calories I burn during exercise?

Partially, but not fully. Exercise calorie estimates from wearables and gym machines tend to overcount by 20-40%. If your tracker says you burned 400 calories on a run, eating back 200-250 of those calories is a safer approach. Alternatively, choose a TDEE multiplier that already factors in your exercise and skip manual additions entirely.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the calories your body needs at complete rest to sustain basic life functions. TDEE (Total Daily Energy Expenditure) is BMR plus all additional calories burned through physical activity, digestion (thermic effect of food), and non-exercise movement (fidgeting, walking to the car, standing). TDEE is the number you actually use for meal planning because nobody lies in bed motionless all day.

Is 1,200 calories enough for weight loss?

For most adults, 1,200 calories is near the minimum safe threshold. It may be appropriate for smaller, sedentary women under medical supervision, but it’s too low for most men and active women. Eating too little causes muscle loss, fatigue, nutrient deficiencies, and metabolic adaptation that makes future weight loss harder. A more sustainable approach is a 500-calorie deficit from your personal TDEE, even if that means eating 1,800 or 2,000 calories.

How often should I recalculate my calorie needs?

Recalculate every time you lose or gain 10-15 pounds, change your activity level significantly, or hit a plateau lasting more than 3 weeks. Your body adapts to both calorie intake and exercise routines, so periodic reassessment keeps your targets aligned with your actual energy expenditure.