Free Calorie Calculator

Find out exactly how many calories you need each day to maintain weight, lose fat, or build muscle β€” based on your body stats and activity level.

Mifflin-St Jeor Formula Metric & Imperial Macro Breakdown Included

Your Details

Biological Sex
Activity Level

How This Calculator Works

This tool uses the Mifflin-St Jeor equation β€” the most accurate BMR formula validated for healthy adults β€” combined with an activity multiplier to estimate your Total Daily Energy Expenditure (TDEE).

Step 1 β€” Basal Metabolic Rate (BMR)

Your BMR is the number of calories your body burns at complete rest β€” just to keep organs functioning, regulate temperature, and maintain basic biological processes. It accounts for roughly 60–70% of your total daily energy expenditure.

BMR is primarily determined by body size (height and weight), age, and sex. Larger bodies require more energy to maintain, and BMR decreases gradually with age.

Step 2 β€” Total Daily Energy Expenditure (TDEE)

TDEE is your BMR multiplied by an activity factor that accounts for how much energy you burn through movement β€” from daily walking and exercise to a physically demanding job. A sedentary office worker has a much lower TDEE than someone training twice a day.

Step 3 β€” Calorie Targets

Once you have your TDEE (maintenance), you can set a target based on your goal:

  • Lose fat: eat 250–500 kcal below maintenance
  • Maintain weight: eat at maintenance
  • Build muscle: eat 250 kcal above maintenance

Step 4 β€” Macros

Macronutrients β€” protein, carbohydrates, and fat β€” are the three energy sources in food. The calculator uses a balanced 30 / 40 / 30 split (protein / carbs / fat) as a starting point. You can fine-tune this in the Nutrido app based on your preferences and goals.

Mifflin-St Jeor Formula

Men: BMR = 10W + 6.25H − 5A + 5 Women: BMR = 10W + 6.25H − 5A − 161

W = weight in kg  ·  H = height in cm  ·  A = age in years

Activity Multipliers
Activity Level Multiplier
Sedentary (desk job, no exercise)Γ—1.20
Lightly active (1–3 days/week)Γ—1.375
Moderately active (3–5 days/week)Γ—1.55
Very active (6–7 days/week)Γ—1.725
Extra active (physical job + daily training)Γ—1.90

What to Do After Calculating Your Calories

Knowing your calorie target is step one. The hard part is staying consistent. Nutrido is the fastest way to track what you actually eat β€” with AI photo analysis and manual logging.

Set Your Calorie Goal in Nutrido

Enter your daily calorie target from this calculator directly into Nutrido. Set custom macro goals for protein, carbs, and fat to match your specific plan. Your dashboard shows progress throughout the day in real time.

Log Meals with AI Photo Analysis

Take a photo of any meal and Nutrido's AI instantly estimates the calories and macros β€” no manual searching needed. For home-cooked meals, use the ingredient-by-ingredient mode for precise tracking.

Track Progress and Adjust

See your calorie and macro balance update with every meal. Track hydration alongside nutrition. Review your weekly trends and adjust your intake or activity level as your goals evolve.

Frequently Asked Questions

Common questions about calories, TDEE, deficits, and macros β€” answered concisely.

How many calories do I need per day?

Your daily calorie needs depend on your sex, age, height, weight, and activity level. Most adults need between 1,600 and 3,000 kcal per day. Use this calculator to get a personalized estimate based on the Mifflin-St Jeor equation.

What is a calorie deficit and how large should mine be?

A calorie deficit means eating fewer calories than you burn. A mild deficit of 250 kcal/day leads to about 0.25 kg (0.5 lb) of fat loss per week. A standard deficit of 500 kcal/day leads to roughly 0.5 kg (1 lb) per week. Larger deficits can lead to muscle loss and are generally not recommended without medical guidance.

What is TDEE and how is it calculated?

TDEE stands for Total Daily Energy Expenditure β€” the total number of calories your body burns in a day, including activity. It is calculated by multiplying your Basal Metabolic Rate (BMR) by an activity multiplier ranging from 1.2 (sedentary) to 1.9 (very active).

What is the Mifflin-St Jeor equation?

The Mifflin-St Jeor equation estimates your Basal Metabolic Rate (BMR) β€” the calories your body needs at rest. For men: BMR = 10 Γ— weight (kg) + 6.25 Γ— height (cm) βˆ’ 5 Γ— age + 5. For women: BMR = 10 Γ— weight (kg) + 6.25 Γ— height (cm) βˆ’ 5 Γ— age βˆ’ 161. It is considered the most accurate BMR formula for the general population.

How should I split my calories into macros?

A common balanced split is 30% protein, 40% carbohydrates, and 30% fat. For fat loss, increasing protein to 35% helps preserve muscle mass. For muscle gain, carbohydrates can be raised to 45–50%. Nutrido lets you set custom macro targets in the app.

How accurate is this calorie calculator?

This calculator uses the Mifflin-St Jeor formula, which is validated in peer-reviewed research and considered the most accurate predictive equation for most healthy adults. It estimates within Β±10% for most people. Individual factors like muscle mass, metabolic conditions, and sleep quality can affect actual calorie needs.

What should I do after calculating my calories?

Once you know your calorie target, the key is consistent daily tracking. Download Nutrido to log meals using AI photo analysis or manual entry, set your custom calorie and macro goals, and monitor your progress over time. Tracking what you eat is the single most effective behavior for reaching nutrition goals.

Track Your Calories in Nutrido

You've calculated your calorie target. Now make it stick. Nutrido turns your numbers into daily habits β€” log meals in seconds with AI photo analysis, track macros, and watch your progress build over time.

πŸ“± Free on iOS & Android
✨ AI-powered meal photo logging
🎯 Custom calorie & macro goals