Calorie calculator with Mifflin-St Jeor

Enter your details to estimate BMR, TDEE, and daily calories for your training goal.

01 THE PROFILE

02 THE ENGINE

03 THE OBJECTIVE

Target Daily Intake
2,480KCAL
Maintenance2,980 KCAL
Strategy Adj.-500 KCAL

Macro Blueprint

Protein (40%)248g
Carbohydrates (35%)217g
Fats (25%)69g
01

Anabolic Window

Prioritize 40g protein within 60 minutes of finishing training.

02

Volume Eating

Use high-volume vegetables to maximize satiety on deficit days.

03

Micro Sync

Ensure electrolyte intake on morning sessions or fasted cardio days.

Calculate your calories with scientific accuracy

This calculator uses the Mifflin-St Jeor formula to estimate your basal metabolism (BMR) and total daily expenditure (TDEE), then adjusts calories to your goal.

What you get in seconds

  • Daily calories based on your goal
  • Clear BMR and TDEE results
  • Suggested macronutrient split

How it works

Enter sex, age, weight, and height to estimate BMR.

Select your activity level to calculate TDEE.

Pick a goal and we adjust calories to a realistic plan.

Best for people who want to

  • Lose fat without losing muscle
  • Build muscle with a controlled surplus
  • Maintain weight with precision
The Science Behind

Mifflin‑St Jeor Formula

How does it work?

The Mifflin‑St Jeor formula calculates your Basal Metabolic Rate (BMR), the calories your body needs at rest to maintain vital functions like breathing, circulation, and temperature regulation.

Men:

BMR = (10 × weight) + (6.25 × height) - (5 × age) + 5

Women:

BMR = (10 × weight) + (6.25 × height) - (5 × age) - 161

Then we multiply BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE), the total calories you burn each day.

History

The equation was developed in 1990 by Drs. M.D. Mifflin and S.T. St Jeor with their research team at the University of Nevada.

It was created as an update to the 1918 Harris‑Benedict formula, since lifestyles and body composition patterns had changed significantly during the 20th century.

Later studies have shown this formula to be up to 5% more accurate than other predictive equations, making it the gold standard for basal metabolism calculation.

Understand Your Goal

Each goal requires a different nutrition approach. Here is how we adjust calories based on what you want to achieve.

Surplus or deficit intensity

For surplus and deficit goals, the final calorie adjustment can vary based on the selected intensity: light, moderate, or aggressive.

Build Muscle

To gain muscle you need a calorie surplus, meaning you consume more calories than you burn.

+300 kcal

above your TDEE

  • Higher protein share (30%)
  • Carbs for energy (45%)
  • Healthy fats (25%)

Lose Body Fat

To lose fat you need a calorie deficit by eating fewer calories than you burn sustainably.

-500 kcal

below your TDEE

  • High protein to preserve muscle (35%)
  • Moderate carbs (35%)
  • Fats for satiety (30%)

Maintain Weight

To maintain current weight you need to match calories burned, achieving energy balance.

= TDEE

balanced calories

  • Moderate protein (25%)
  • Carbs as energy base (50%)
  • Essential fats (25%)

Recomposition

Recomposition means losing fat and gaining muscle at the same time. Ideal for beginners or returning athletes.

-100 kcal

light deficit

  • High protein for muscle synthesis (35%)
  • Carbs for performance (40%)
  • Fats for hormones (25%)

Activity Levels

Your activity level determines how many calories you burn beyond your basal metabolism.

Sedentary

×1.2

Little to no exercise per day

Light activity

×1.375

Light exercise 1-3 days/week

Moderate activity

×1.55

Moderate exercise 3-5 days/week

Intense activity

×1.725

Intense exercise 6-7 days/week

Very intense activity

×1.9

Physical work + daily exercise

Questions?

If you have questions about using the calculator or need personalized nutrition guidance, reach out.

Contact us

Privacy Policy

Data we process

GainWise calorie calculator processes your data (sex, age, weight, height, activity level, and goal). We collect this information anonymously and in aggregate to improve our services and recommendations.

Use of anonymous data

Collected data is used only for statistical analysis, improving recommendation accuracy, and developing new features. We never sell or share data with third parties for advertising.

Cookies

We use essential cookies to remember your theme preference (light/dark) and analytics cookies to understand how you use the tool. You can disable cookies in your browser at any time.

Your rights

Because data is anonymous, we can't identify individuals. We respect your privacy and you can contact us with questions about our data practices.

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