Daily calorie estimator (BMR & TDEE)
This tool applies the Mifflin–St Jeor formula for resting metabolism, then scales it by a classic activity factor so you can see a ballpark maintenance calorie range. It is a conversation starter for planning—not a diagnosis.
Not medical advice. Use professional guidance for clinical nutrition, eating disorders, pregnancy, or sport-specific periodization.
About you
Estimate
BMR (at rest)
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TDEE (maintenance ballpark)
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TDEE combines BMR with your selected activity multiplier. Real energy needs swing with sleep, stress, steps, and training load.
What BMR and TDEE actually mean
Basal metabolic rate is the energy your body would spend lying quietly awake, keeping organs running, maintaining temperature, and repairing tissue. Equations like Mifflin–St Jeor predict that floor from weight, height, age, and sex because those variables correlate with how much metabolically active tissue you carry. They are not a photograph of your mitochondria—two people with identical measurements can still differ—but they beat random guessing when you need an order-of-magnitude anchor.
Total daily energy expenditure adds movement: walking between meetings, carrying groceries, formal workouts, fidgeting, even standing versus sitting. Nutrition researchers often split those pieces into activity thermogenesis and exercise, but for a free web tool a single multiplier is the pragmatic compromise. If you toggle from “sedentary” to “very active,” you should expect a wide swing in the output—that is the model telling you workload dominates as much as body size.
Practical uses (and limits) of a calorie estimate
Someone resetting food habits might use TDEE as a maintenance reference before deciding whether to eat slightly above or below it for their goal. Coaches sometimes bracket a range by running the formula at two activity assumptions when a client’s schedule is irregular. Medical nutrition therapy, on the other hand, layers disease-specific adjustments, lab values, and monitoring that a static page cannot provide. Treat the numbers here as starting vocabulary, not a prescription etched in stone.
Frequently asked questions
- What equation powers this calorie calculator?
- It uses the Mifflin–St Jeor equation for resting metabolic rate, then multiplies by an activity factor to approximate total daily energy expenditure (TDEE). Outputs are rounded whole kilocalories per day.
- Is this page medical nutrition advice?
- No. It is an educational estimator based on population formulas. Pregnancy, illness, medications, and elite training all change needs; a registered dietitian or physician should interpret real plans.
- Why do men and women get different BMR at the same size?
- The published Mifflin–St Jeor coefficients include a sex term reflecting typical lean mass differences in the reference populations the equation was fitted to. Individual variation still matters more than any single formula.
- Which activity level should I choose?
- Pick the description that best matches your average week, not your busiest day. Sedentary is mostly seated work; very active implies hard physical labor or intense daily training. When unsure, moderate is a common middle setting.
- Does the site store my height or weight?
- These pages are static files running in your browser; values are not sent to a server by this calculator unless your own network tools inject something else. Clearing the page clears the fields.