Maintenance Calorie Calculator
Your maintenance calories are the number of calories you need to eat each day to keep your weight exactly where it is. Not to lose, not to gain. Just to maintain. Get this number right and weight management becomes a matter of arithmetic rather than guesswork.
The scientific term is Total Daily Energy Expenditure (TDEE), and calculating it accurately has been an active area of nutrition research since the 1990s. This calculator uses the Mifflin-St Jeor equation, the most validated and widely recommended formula for estimating resting metabolic rate in healthy adults (Academy of Nutrition and Dietetics, 2005).
How Maintenance Calories Are Calculated
The calculation happens in two steps. First, your Basal Metabolic Rate (BMR) is estimated using the Mifflin-St Jeor equation. BMR represents the calories your body burns at complete rest just to keep you alive.
For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
For women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
That BMR figure then gets multiplied by an activity factor to account for everything you do outside of lying still:
| Activity Level | Multiplier |
|---|---|
| Sedentary (desk job, little exercise) | 1.2 |
| Lightly active (light exercise 1-3 days/week) | 1.375 |
| Moderately active (moderate exercise 3-5 days/week) | 1.55 |
| Very active (hard exercise 6-7 days/week) | 1.725 |
| Extra active (physical job or twice-daily training) | 1.9 |
The result, BMR × activity multiplier, is your TDEE, your maintenance calorie number. Mifflin and colleagues derived this equation from 498 healthy subjects and found it outperformed the older Harris-Benedict equation, which overestimated measured resting energy expenditure by around 5% (Mifflin et al., 1990, PMID: 2305711).
Understanding Your Results
A 2005 systematic review by Frankenfield and colleagues compared all major predictive equations across hundreds of subjects. The Mifflin-St Jeor equation predicted resting metabolic rate within 10% of the measured value in more individuals than the Harris-Benedict, Owen, or WHO equations (PMID: 15883556).
What “within 10%” means in practice: if your calculated maintenance is 2,200 calories, your true maintenance is somewhere between 1,980 and 2,420. That’s still a useful range. Most people significantly underestimate their calorie needs, and having even a rough anchor number helps.
Accuracy does vary by body composition. A 2013 study by Frankenfield found the equation was accurate for 87% of non-obese participants but dropped to 75% accuracy in participants with obesity (PMID: 23631843). The further you are from the population the equation was built on, the more you should treat your result as a starting estimate rather than a fixed number.
When to Use This Calculator
Setting a weight-loss or weight-gain target. To lose weight, you need to eat below your TDEE. To gain, above it. Without knowing your maintenance number, any calorie target is just a guess. This gives you the baseline.
Figuring out why your weight isn’t changing. If you’ve been eating what feels like very little but your weight is stuck, calculating your actual TDEE often reveals you’re closer to maintenance than you realized. The same goes in reverse.
Adjusting calories after a lifestyle change. Start a new job with more activity, add a serious training program, or shift to mostly sedentary work from a physically demanding role, and your maintenance number changes. Recalculate whenever your activity level shifts significantly.
Understanding energy balance. Consuming calories equal to your TDEE should maintain your current weight under stable conditions. This calculator makes that relationship concrete rather than abstract.
Limitations
The formula was built on measured data, but it has real boundaries. Individual metabolic variation runs roughly 10-15% among people with identical age, sex, height, and weight. Two people who look the same on paper can have genuinely different calorie needs, and no equation can fully account for that.
The activity multipliers add another layer of estimation. They provide a general framework, but actual energy expenditure varies based on exercise intensity, non-exercise activity thermogenesis (fidgeting, posture, small movements throughout the day), and individual efficiency. The gold standard for measuring TDEE is the doubly labeled water (DLW) method, which tracks isotope turnover over weeks. A calculator can’t replicate that precision.
Research from Pontzer and colleagues (2016) adds another wrinkle: the body appears to constrain total energy expenditure at higher activity levels. Very active individuals may not burn as many additional calories as the multipliers suggest because the body adapts by reducing expenditure elsewhere (PMID: 26832439). This “constrained energy model” is an active area of research, but it’s a reason to treat the very-active and extra-active multipliers with some skepticism.
Prediction equations may also be less accurate for individuals with obesity, as noted above. If you fall into this category, use your result as a starting point and adjust based on what you observe over four to six weeks of consistent intake.
Tips for Accuracy
- Weigh yourself and measure height carefully. Even small errors compound through the equation. Use a reliable scale, same time of day, same conditions each time.
- Be honest about activity level. Most people overestimate. If you work out three times a week but sit at a desk the rest of the time, “lightly active” is probably more accurate than “moderately active.”
- Track for at least four weeks before adjusting. Week-to-week weight fluctuates due to water retention, hormones, and food volume in your gut. Four weeks of data smooths that noise.
- Use your result as a starting point, not a fixed answer. If you eat at your calculated maintenance for a month and gain weight, your true maintenance is slightly lower. Adjust by 100-150 calories and observe again.
- Recalculate as your weight changes. Your BMR is calculated from your current weight. If you lose 20 pounds, your maintenance calories drop too. Run the numbers again.
Frequently Asked Questions
What’s the difference between BMR and TDEE? BMR (Basal Metabolic Rate) is the calories your body burns at complete rest, essentially the energy cost of being alive. TDEE (Total Daily Energy Expenditure) includes BMR plus all the calories you burn through movement and activity. Your maintenance calorie number is your TDEE, not your BMR. Eating at your BMR would put most people in a significant calorie deficit.
Why does this calculator use Mifflin-St Jeor instead of Harris-Benedict? The Harris-Benedict equation has been in use since 1919. It’s not wrong, but it consistently overestimates resting energy expenditure by about 5% compared to measured values. A 2005 systematic review found Mifflin-St Jeor to be more reliable across a broader range of people (Frankenfield et al., 2005, PMID: 15883556), which is why the Academy of Nutrition and Dietetics recommends it for estimating RMR in healthy adults.
How accurate is this calculator for people with a lot of muscle mass? The Mifflin-St Jeor equation uses total body weight, not lean mass. Muscle is metabolically more active than fat, so people with high muscle mass may find this calculator slightly underestimates their actual needs, while those with higher body fat percentages may find it slightly overestimates. For more precision, calculating from lean body mass using the Katch-McArdle formula is an alternative, though it requires knowing your body fat percentage.
How often should I recalculate my maintenance calories? Recalculate any time your weight changes by more than 10 pounds, your activity level changes significantly, or your results don’t match what you’re observing. Age and body composition shift slowly, but a significant change in your daily life warrants a fresh calculation.
Can I lose weight by eating at my maintenance calories? No. By definition, eating at your maintenance calories should hold your weight stable. To lose weight, you need a calorie deficit, meaning eating below your TDEE. A common starting point is 500 calories below maintenance, which creates roughly a pound of weight loss per week in theory, though individual results vary based on metabolic adaptation and body composition.
References
- Mifflin, M. D., St Jeor, S. T., Hill, L. A., Scott, B. J., Daugherty, S. A., & Koh, Y. O. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241–247. PMID: 2305711.
- Frankenfield, D., Roth-Yousey, L., & Compher, C. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association, 105(5), 775–789. PMID: 15883556.
- Frankenfield, D. C. (2013). Bias and accuracy of resting metabolic rate equations in non-obese and obese adults. Clinical Nutrition, 32(6), 976–982. PMID: 23631843.
- Black, A. E., Coward, W. A., Cole, T. J., & Prentice, A. M. (1996). Human energy expenditure in affluent societies: an analysis of 574 doubly-labelled water measurements. European Journal of Clinical Nutrition, 50(2), 72–92. PMID: 8641250.
- Pontzer, H., Durazo-Arvizu, R., Dugas, L. R., Plange-Rhule, J., Bovet, P., Forrester, T. E., Lambert, E. V., Cooper, R. S., Schoeller, D. A., & Luke, A. (2016). Constrained total energy expenditure and metabolic adaptation to physical activity in adult humans. Current Biology, 26(3), 410–417. PMID: 26832439.
- FAO/WHO/UNU. (2004). Human Energy Requirements: Report of a Joint FAO/WHO/UNU Expert Consultation. Food and Agriculture Organization of the United Nations.