Calorie & Macro Calculator — Find Your TDEE

Before you change how you eat, it helps to know two numbers: how much energy your body burns at rest (your BMR) and how much you burn across a full day (your TDEE, or maintenance calories). This calculator estimates both with the Mifflin-St Jeor equation — the formula dietitians and researchers reach for most often — then turns them into calorie and macro targets for whatever your goal is: losing fat, maintaining, or building.

Enter your details below. It takes about 30 seconds, and nothing is stored.

What is BMR (basal metabolic rate)?

Your BMR is the number of calories your body burns at complete rest, just to keep you alive — breathing, circulating blood, holding your temperature, running your organs. It’s the largest single piece of your daily calorie burn, usually around 60–70% of the total. This calculator estimates it from your sex, age, height, and weight.

What is TDEE (total daily energy expenditure)?

Your TDEE is everything your BMR covers plus the energy you spend moving — workouts, walking, fidgeting, even digesting food. We estimate it by multiplying your BMR by an activity factor, from 1.2 for mostly sedentary up to 1.9 for very physically active. Your TDEE is your maintenance level: eat around it and your weight stays roughly stable.

Not sure which activity level to pick? A good rule of thumb: choose “sedentary” if most of your day is sitting, “lightly active” for 1–3 workouts a week, “moderately active” for 3–5, and reserve “very” or “extra active” for hard daily training or a physically demanding job. When in doubt, pick the lower option — it’s easy to overestimate.

How many calories should I eat to lose or gain weight?

To lose weight you eat below your TDEE; to gain, above it. A rough, widely used rule is that a deficit of about 500 calories a day works out to roughly a pound of fat per week — a simplification, but a useful starting point. Smaller changes (around 250 calories a day) are often easier to sustain and just as effective over time. The calculator caps targets at a safe minimum, because cutting too aggressively tends to backfire: it’s harder to stick to and can cost you muscle along with fat.

What are macros, and how should I split them?

Macros — protein, carbohydrates, and fat — are simply where your calories come from. This calculator sets protein first, at about 1.8 g per kilogram of body weight, which sits inside the 1.4–2.0 g/kg range the International Society of Sports Nutrition recommends for active people building or maintaining muscle. Fat is set at about 25% of calories, and the rest comes from carbohydrates to fuel training and daily activity. Protein is prioritized because it helps preserve muscle in a deficit and keeps you fuller.

How this calculator works

BMR is calculated with the Mifflin-St Jeor equation (Mifflin MD, St Jeor ST, et al., American Journal of Clinical Nutrition, 1990): for men, 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women, the same with −161 instead of +5. TDEE multiplies BMR by a standard activity factor (1.2–1.9). Goal targets apply a calorie deficit or surplus, and the protein target follows the ISSN position stand on protein and exercise (Jäger et al., 2017). All values are population estimates — actual needs vary with genetics, body composition, hormones, and other factors.

A note on eating enough

Lower isn’t always better. Eating well below your needs for long stretches is hard to sustain, can drain your energy and training, and may cost you muscle. That’s why the calculator flags any target that falls below your BMR or a safe minimum. If you have a history of disordered eating, please talk to a qualified professional before using calorie targets — and treat these numbers as an educated starting point, not a personalized plan.

Frequently Asked Questions