Estimate how many calories you burn per day — your Total Daily Energy Expenditure — from your BMR and activity level using the Mifflin-St Jeor equation.
Units and body information
cm
kg
years
Ages 18–100. This estimate is not intended for people under 18.
Adds a Katch-McArdle comparison alongside the primary Mifflin-St Jeor estimate. Body-fat measurements themselves can carry significant error.
Activity level
Activity level is often the largest source of uncertainty in a TDEE estimate.
Goal
Estimate only — not medical advice. Consult a qualified healthcare professional before acting on this result.
Estimated daily energy expenditure
Female reference
2,420 calories/day
BMR 1,563 calories/day
Male reference
2,680 calories/day
BMR 1,729 calories/day
The published equation uses a different constant for each reference. Choose one above for a single estimate, its maintenance range and the goal scenarios.
Weight-loss targets here never go below 1,200 calories a day for the female reference or 1,500 for the male, and never plan loss faster than 2 lb (0.9 kg) a week. Not for anyone under 18, pregnant or breastfeeding.
What this tool covers
With a maintenance range and calorie scenarios for losing, maintaining, or gaining weight.
BMR and TDEE estimate
Maintenance calorie range
Loss and gain scenarios
Optional body-fat comparison
Mifflin-St Jeor Metric & US units Not an exact measurement
Why the maintenance figure comes back as a range, not one number
TDEE, or Total Daily Energy Expenditure, is an estimate of the total energy your body uses in a day, including resting needs (BMR) and physical activity. It is the calorie figure most people mean when they talk about “maintenance calories” — the intake that would be expected to hold your weight roughly steady.
Because the activity factor is an approximation of a whole week rather than a measurement, this calculator shows an estimated maintenance range (approximately ±10% around TDEE) instead of presenting one number as a perfectly precise target.
Eating exactly the TDEE figure makes sense only if your goal is to maintain your current weight. This calculator shows a maintenance range (not one exact number) because TDEE is an estimate — eating anywhere within that range would be expected to keep weight roughly stable for most people. For weight loss or gain, see the deficit/surplus scenarios below the main result.
The gap between the BMR line and the TDEE line is the activity factor
Basal Metabolic Rate (BMR) is the energy your body would use over 24 hours at complete rest — breathing, circulation, cell repair, and other baseline processes. It typically accounts for the largest share of daily energy use for most people.
Total Daily Energy Expenditure (TDEE) starts from BMR and adds everything else: digesting food, incidental daily movement, and any structured exercise. TDEE is always equal to or greater than BMR, and the gap between the two is driven almost entirely by the activity factor.
Which equations this runs: Mifflin-St Jeor by default, Katch-McArdle if you know your body fat
Male reference
BMR = 10w + 6.25h − 5a + 5
w = weight (kg), h = height (cm), a = age (years).
Female reference
BMR = 10w + 6.25h − 5a − 161
Same weight/height/age inputs, different published constant.
This calculator estimates your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor equation from your age, height, weight, and equation reference, then multiplies BMR by an activity factor (1.2 to 1.9) that reflects how much you move in a typical week. TDEE = BMR × activity factor.
The published equation uses two different constants depending on the reference population it was validated against — this calculator calls that choice “equation reference” rather than assuming it from any other field, and it does not define your gender identity. Once BMR is calculated, TDEE = BMR × activity factor, using the conventional multipliers in the next section. This calculator keeps every intermediate value at full precision internally and only rounds for display (BMR to the nearest whole calorie; TDEE, daily targets, and the maintenance range to the nearest 10 calories; weekly totals to the nearest 100), so chained results never accumulate rounding error.
Mifflin-St Jeor is validated for both men and women. Choose the “female reference” equation option (this calculator calls it equation reference rather than gender, since it does not define your gender identity) to use the correct published constant for the BMR formula.
This calculator does not use the Harris-Benedict formula. It uses Mifflin-St Jeor, which is generally considered more accurate than the older Harris-Benedict equation for most people, based on more recent validation research. The two formulas can give noticeably different results for the same inputs; if you specifically need Harris-Benedict, this calculator will not reproduce it.
No formula-based estimate is exact, but if you know your body fat percentage, the optional Katch-McArdle comparison on this page uses lean body mass instead of total weight, which is typically more accurate for people whose body composition differs a lot from average (very lean or very muscular). Otherwise, Mifflin-St Jeor is one of the better-validated general-population formulas.
The formula and activity-factor approach are not country-specific, and the calculator supports both metric (kg/cm) and US customary (lb/ft-in) units, so it works the same regardless of where you are.
Activity level is the input most likely to move your estimate
Activity level is often the largest source of uncertainty in a TDEE estimate — two people with identical BMR can have real energy needs that differ by 50% or more once activity is factored in.
Activity levels, factors, and typical weekly patterns
Level
Factor
Typical pattern
Sedentary
1.2
Little structured exercise; mostly seated daily routine.
Lightly active
1.375
Light exercise approximately 1–3 days per week.
Moderately active
1.55
Moderate exercise approximately 3–5 days per week.
Very active
1.725
Hard exercise approximately 6–7 days per week.
Extra active
1.9
Very hard training, a highly physical occupation, or two-a-day training.
Pick the description that matches your typical week, not your best week or an occasional workout. Someone with a desk job who exercises twice a week is usually “lightly active,” not “moderately active” — it is common to overestimate this factor, which is one reason the maintenance range is shown as a band rather than a single number.
Following one 80 kg example from BMR to a 10% deficit target
Take a 30-year-old using the male reference equation, at 80 kg and 180 cm, who is moderately active (factor 1.55):
TDEE = 1,780 × 1.55 = 2,759 cal/day, displayed as 2,760 calories/day (rounded to the nearest 10), with an estimated maintenance range of roughly 2,480–3,030 calories/day.
For a gentle 10% weight-loss deficit, the daily target would be approximately 2,760 × 0.9 ≈ 2,480 calories/day — about 280 calories/day, or roughly 2,000 calories/week, below maintenance.
Testing the number against your own weight trend over 2–3 weeks
A TDEE number is most useful as a starting point to test, not a fact to obey. A practical way to use it:
Follow a consistent intake for approximately 2–3 weeks.
Track your average body weight over that time rather than reacting to any single day (day-to-day weight moves with water, sodium, and digestion, not just fat or muscle).
Compare the observed trend with this estimate.
Adjust gradually if your actual results differ from the estimate.
Remember that changes in exercise, occupation, illness, sleep, medication, and body weight can all change your real energy needs over time.
TDEE calculators are estimates, not measurements. The Mifflin-St Jeor equation is one of the better-validated predictive formulas for resting energy expenditure, but individual metabolism varies, and the activity factor is a broad approximation of a whole week of movement. Treat the number as a starting point to test against your own results over a few weeks, not a lab measurement.
Recalculate whenever your weight changes meaningfully (roughly 2–3 kg / 5 lb or more), or when your activity level, occupation, or exercise routine changes. Otherwise, revisiting the estimate every few weeks alongside your own tracked results is a reasonable rhythm.
Smartwatches estimate energy expenditure from heart rate, motion sensors, and their own internal models, which can differ noticeably from formula-based estimates like this one, especially for resting energy. Treat a wearable’s number as another estimate to compare against this one, not a more accurate ground truth by default.
Why this number usually gets smaller as you lose weight
Both BMR and TDEE are calculated from body weight, so as weight decreases, the formula predicts a lower BMR and therefore a lower TDEE. This is a normal, expected part of losing weight (not a sign of a “broken metabolism”), and it is exactly why the Calorie Deficit Calculator recalculates BMR and TDEE at each step of its projection rather than using one fixed number throughout.
Where a general-population formula is least likely to fit you
TDEE and BMR estimates from any formula, including Mifflin-St Jeor, carry real uncertainty. This calculator’s estimate may be less representative for:
Competitive and highly trained athletes, whose energy needs and body composition can differ substantially from the general adult population this formula was validated on.
Pregnancy and breastfeeding, when energy needs change in ways this calculator does not model.
People under 18, for whom this estimate is not intended (growing bodies have different, changing energy needs). An age under 18 shows a notice in place of the estimate.
People with diagnosed metabolic, thyroid, or hormonal conditions, medically supervised diets, or recent significant weight change, illness, or surgery — all of which can shift real energy needs away from a general-population formula.
Anyone using prescription weight-management medication — this calculator must not be used to start, stop, or adjust any medication.
This calculator is not suitable during pregnancy. Energy needs during pregnancy and breastfeeding change in ways this general adult calculator does not account for, and calorie restriction is not appropriate during pregnancy without direct clinical guidance. Speak with a midwife, obstetrician, or registered dietitian for pregnancy-specific nutrition guidance. Ticking “pregnant or breastfeeding” in the calculator shows a notice in place of the estimate.
In every case, this tool provides an educational estimate to discuss with, not replace, a qualified healthcare professional or registered dietitian.
Sources and methodology
Formula: Mifflin-St Jeor resting energy expenditure equation, as published in the original clinical research below. Activity multipliers: the conventional 1.2–1.9 activity-factor approach commonly used alongside Mifflin-St Jeor, clearly labelled here as an approximation. Floors, pace cap and limits: the weight-loss scenarios never go below 1,200 calories a day for the female reference or 1,500 for the male, or plan loss faster than 2 lb (0.9 kg) a week. Each source below says what it backs.
Backs the floors on the weight-loss scenarios: it prescribes 1,200–1,500 calories a day for women and 1,500–1,800 for men to lose weight, and the scenarios use the lower end of each.
This calculator implements the published Mifflin-St Jeor formula and the conventional activity-factor approach; it is an independent implementation and is not affiliated with, endorsed by, or a reproduction of the NIH Body Weight Planner or any other named tool.
Related calculators
Calorie DeficitCalculate a daily calorie deficit and an adaptive weight-loss timeline range from your TDEE, with a safety-floor warning and a scenario comparison.
BMICalculate BMI in metric or imperial units, see your adult category and healthy-weight range, with clear limitations and a separate under-18 result.
This page is the work of Jay Sudha, who is not a doctor, dietitian, or other licensed clinician, and no licensed medical professional has vetted it yet. Treat it as general education, not medical advice — for anything that matters for your health, talk to a qualified professional. This calculator provides an educational estimate, not medical advice.
Actual energy needs and weight changes vary by age, sex, body composition, medical conditions, activity level, and professional guidance.
It is not intended for people under 18, and may not be suitable without professional guidance during pregnancy or breastfeeding,
for a history of an eating disorder, for competitive athletes, for diabetes or metabolic disease, for kidney, liver,
or heart conditions, for recovery from surgery or illness, for anyone using prescription weight-management medication, or for anyone advised to follow a medically supervised diet.
This calculator must not be used to start, stop, or adjust any medication.
Published the TDEE calculator: Mifflin-St Jeor BMR/TDEE engine, five activity levels, maintenance range, and weight-loss/weight-gain calorie scenarios.
Added as the Health category's second tool, alongside BMI.
The weight-loss scenarios now hold the same calorie floors and 2 lb-a-week pace cap; an age under 18 or pregnancy or breastfeeding shows a notice in place of the scenarios; each source now states what it backs.
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