BMR & TDEE Calculator

BMR vs. TDEE — what's the difference?

Your BMR (Basal Metabolic Rate) is the energy your body burns at complete rest just to stay alive — breathing, circulation, keeping your organs running. Your TDEE (Total Daily Energy Expenditure) is the bigger number: BMR plus everything you do on top of it, from walking to the kitchen to a hard workout. TDEE is your maintenance calories — eat that much and your weight holds steady.

How it's calculated

This tool uses the Mifflin–St Jeor equation, the formula clinicians consider the most accurate for most people:

• Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
• Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161

TDEE then multiplies BMR by an activity factor from 1.2 (sedentary) up to 1.9 (hard daily training or a physical job). Honesty here matters — most people overestimate how active they are, which inflates the number.

Using these numbers

• To maintain your weight, eat around your TDEE.
• To lose weight, eat below it — a 500 cal/day deficit is roughly 1 lb (0.45 kg) per week.
• To gain muscle, eat a modest surplus above it alongside strength training.

FAQ

How accurate is the estimate?

It's a solid starting point, but real metabolism varies with muscle mass, genetics, hormones, and more. Treat it as a baseline: track your weight for a couple of weeks and adjust your intake up or down based on what actually happens.

Which activity level should I pick?

Base it on your whole week, not your best day. If you sit most of the day and train a few times a week, "lightly" or "moderately active" is usually closer to the truth than "very active."

Is this BMR/TDEE calculator free and private?

Yes, it's free with no account required, and your height, weight, and age are used only for the calculation in your browser. Nothing you enter is uploaded or stored.

Does it work on my phone?

Yes. The calculator is fully responsive, so you can work out your maintenance calories on a phone, tablet, or desktop with the same results.

Why does the Mifflin–St Jeor formula not ask for body fat?

Mifflin–St Jeor estimates BMR from height, weight, age, and sex alone, which is accurate for the general population. Formulas like Katch–McArdle use lean body mass instead and can be more precise if you know your body-fat percentage, but they require an accurate measurement most people don't have.

How many calories should I cut to lose weight?

A deficit of about 500 calories below your TDEE produces roughly one pound of fat loss per week, while staying sustainable. Aggressive cuts below your BMR are hard to maintain and can cost you muscle, so eat below TDEE but at or above your BMR.