What does this tool do?
This calculator finds your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — using the Mifflin-St Jeor equation. It then estimates your Total Daily Energy Expenditure (TDEE) based on your activity level, making it useful for anyone planning to lose, maintain, or gain weight.
How to use it
- Enter your values into the fields.
- The result is calculated instantly.
- Read or copy the result.
How BMR and TDEE are calculated
Enter your age, gender, height, and weight, and the tool applies the Mifflin-St Jeor equation (men: 10×kg + 6.25×cm − 5×age + 5). The resulting BMR is multiplied by your chosen activity factor — from sedentary (1.2) up to extra active (1.9) — to give TDEE. For example, a 30-year-old man at 70 kg and 175 cm has a BMR of about 1649 kcal and, when lightly active, a TDEE near 2267 kcal. You can switch between metric and imperial units.
Turning the numbers into a calorie goal
Your TDEE is roughly the daily calories that keep your weight stable. To lose weight, a common starting point is eating about 300-500 kcal below TDEE; to gain, add a similar amount. Track your weight weekly and recalculate whenever your routine or activity level changes. Treat the figures as estimates — individual metabolism, muscle mass, and health conditions all shift real needs.
Frequently asked questions
Which formula does this tool use?
It uses the Mifflin-St Jeor equation, widely regarded as one of the most accurate, and generally more realistic than the older Harris-Benedict formula.
What is the difference between BMR and TDEE?
BMR is the energy you burn at rest, while TDEE adds your daily movement and exercise to give your total calorie needs.
What do the activity multipliers mean?
They scale your BMR by how active you are: 1.2 for sedentary up to 1.9 for a very physical job, reflecting calories burned through movement.
Is BMR Calorie Calculator free?
Yes. BMR Calorie Calculator and all 300+ tools on MagmaNex are completely free with no signup or account required.
Is my data safe?
Yes. Everything runs locally in your browser. The data you enter is never sent to a server, stored, or shared.
Does it work on mobile?
Yes. BMR Calorie Calculator works on phones, tablets and desktops — no app download needed.
🔒 Privacy: everything runs in your browser, your data is never sent to a server.