What factors affect BMR?

Your BMR is influenced by age (it decreases as you get older), gender (men typically have higher BMRs due to more muscle mass), and total body composition (muscle burns more calories than fat, even at rest).

Should I eat less than my BMR to lose weight?

Generally, no. Eating below your BMR for extended periods can trigger your body to slow down its metabolism to conserve energy. Most healthy weight loss plans aim for a deficit relative to your TDEE, while still staying near or above your BMR.

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Health & Fitness

BMR Calculator – Metabolism Baseline Service | CalcTools

Calculate your Basal Metabolic Rate (BMR), the number of calories your body burns at complete rest. The foundation of any weight management plan.

Even when you are sleeping or sitting perfectly still, your body is working hard. From pumping blood and breathing to cellular repair and temperature regulation, these 'background' processes require a significant amount of energy. Your Basal Metabolic Rate (BMR) is the exact number of calories your body needs to perform these basic life-sustaining functions. Knowing your BMR is the essential first step in creating any effective diet or fitness plan, as it represents the 'floor' of your daily caloric needs.

Weight (kg)

Height (cm)

Age

Your BMR

1,618kcal/day

Your Basal Metabolic Rate is 1618 calories per day

Weight (kg)70 kg

Height (cm)170 cm

Age30

GenderMale

How it Works

This calculator uses the Mifflin-St Jeor Equation, which is currently considered the most accurate standard for estimating BMR in healthy adults. It factors in your gender, age, weight, and height to provide a personalized daily calorie count.

Calculation Formula

Mifflin-St Jeor Equation

Calculation Examples

1. **Male**: 30 years old, 80kg, 180cm. BMR = **~1,800 kcal/day**. 2. **Female**: 30 years old, 65kg, 165cm. BMR = **~1,400 kcal/day**.

Why use this tool in your daily life?

Without knowing your BMR, dieting is just guessing. This tool provides the mathematical baseline for your metabolism, allowing you to build a nutrition plan that is grounded in your body's actual biological requirements.