Calorie Calculator

Understanding Your Daily Calorie Needs

Managing your weight effectively comes down to one fundamental principle: Energy Balance. Whether you want to shed stubborn fat, build lean muscle, or simply maintain your current physique, understanding your caloric numbers is the first step. Our CalculatorBudy Calorie Calculator simplifies the complex science of metabolism into actionable data.

Instead of guessing how much to eat, you can use science-backed formulas to determine your exact needs. Below, we break down the terminology (BMR, TDEE) and explain how to use your results to transform your body safely.

What is BMR (Basal Metabolic Rate)?

Your Basal Metabolic Rate (BMR) is the number of calories your body burns while performing basic life-sustaining functions. Even if you laid in bed all day without moving a muscle, your body would still need energy to breathe, circulate blood, control body temperature, and grow new cells.

BMR accounts for about 60% to 75% of the calories you burn every day. Because this number is based largely on your height, weight, age, and gender, it is consistent regardless of your daily workout routine. Knowing your BMR is the baseline for all diet plans.

What is TDEE (Total Daily Energy Expenditure)?

While BMR is what you burn at rest, your TDEE is the total amount of calories you burn in a full 24-hour period, factoring in your physical activity. This is the most important number for weight management.

TDEE is calculated by multiplying your BMR by an "Activity Factor." It is crucial to be honest when selecting your activity level to get an accurate result:

• Sedentary (1.2): Desk job, little to no intentional exercise.
• Lightly Active (1.375): Light exercise or sports 1-3 days a week.
• Moderately Active (1.55): Moderate exercise 3-5 days a week.
• Very Active (1.725): Hard exercise 6-7 days a week.
• Extra Active (1.9): Very hard exercise and a physical job (e.g., construction).

How to Use This Calculator for Your Goals

1. For Weight Loss (Cutting)

To lose weight, you must be in a Caloric Deficit. This means consuming fewer calories than your TDEE. A safe, sustainable deficit is typically 500 calories below your TDEE.

Example: If your TDEE is 2,500 kcal, aiming for 2,000 kcal per day should result in approximately 0.5 kg (1 lb) of weight loss per week. Drastic deficits (cutting more than 1,000 calories) are generally not recommended as they can lead to muscle loss, nutritional deficiencies, and metabolic slowdown (often called "starvation mode").

2. For Weight Gain (Bulking)

To gain weight—specifically muscle mass—you need a Caloric Surplus. This means eating more than your TDEE to provide your body with extra energy to build tissue.

A surplus of +250 to +500 calories is usually sufficient for "lean bulking," minimizing fat gain while maximizing muscle growth. Remember, calories alone won't build muscle; you must pair this surplus with resistance training (weight lifting) and adequate protein intake.

3. For Maintenance

If you are happy with your current weight, simply eat at your maintenance calories (your TDEE). This is also useful for "Diet Breaks," where you pause a diet for a week or two to let your metabolism recover before continuing weight loss.

The Science: Which Formula is Used?

CalculatorBudy uses industry-standard formulas to ensure accuracy. By default, we use the Mifflin-St Jeor Equation, but you can change this in the settings.

• Mifflin-St Jeor: Considered the most accurate formula for the general population today. It was introduced in 1990 and has been validated by numerous clinical studies.
• Revised Harris-Benedict: An older formula (revised in 1984). It is still widely used but tends to slightly overestimate calorie needs in overweight individuals.
• Katch-McArdle: This formula is unique because it takes Body Fat Percentage into account. It calculates BMR based on Lean Body Mass rather than total weight. If you know your body fat percentage, this is often the most accurate method for athletes with high muscle mass.

Frequently Asked Questions

Why do I stop losing weight after a few weeks?

As you lose weight, your body becomes smaller and lighter. A lighter body requires less energy to move. Consequently, your BMR and TDEE drop. This is a natural adaptation. If your weight loss stalls (a plateau), you should come back to this calculator, enter your new weight, and recalculate your calorie targets.

Should I eat back the calories I burn from exercise?

Generally, no. The "Activity Level" you selected in the calculator already accounts for your exercise. If you selected "Moderately Active," your exercise calories are already included in your TDEE result. Adding them again would be "double counting" and might prevent weight loss.

Is 1200 calories enough?

For most adults, 1200 calories is the absolute minimum to ensure nutritional adequacy. For many men and active women, 1200 is too low and can result in fatigue, hair loss, and muscle loss. Always aim for the specific "Weight Loss" number provided by the calculator, rather than an arbitrary low number.