Metabolism and maintenance calorie estimator
Estimate your resting metabolism and daily maintenance calories with clearer activity guidance
Use this page to estimate your basal metabolic rate and total daily energy expenditure, understand how activity changes your calorie needs, and get a more practical starting point for maintenance calories.
This tool is written for adults and stays focused on metabolism estimation rather than broader intake planning. If your next question is how many calories to eat for a goal, use the calorie intake calculator. If you want body-size or weight-range context alongside metabolism, compare with the adult BMI calculator, the ideal weight calculator, or the body fat calculator.
BMR and TDEE calculator
Enter your age, sex, height, weight, and activity level to estimate your BMR, your maintenance-calorie starting point, and the activity multiplier used.
Enter your measurements to calculate your BMR and TDEE.
Calculator result
Estimated maintenance calories
Enter your details to see your estimated BMR, maintenance calories, activity multiplier, and practical next-step guidance.
TDEE is usually the more practical maintenance-calorie anchor because it reflects your full day rather than rest alone.
Your interpretation will appear here after calculation.
Use TDEE as a starting point, then track body weight, intake, energy, and routine consistency for 2 to 3 weeks before making large changes.
This calculator uses Mifflin-St Jeor as the default adult BMR estimate and works best as a starting point rather than a direct metabolic measurement.
BMR vs TDEE: what each number means
| Measure | What it means | How to use it |
|---|---|---|
| BMR | Your estimated energy use at full rest before walking, chores, work, or training are added. | Use it to understand your resting metabolic baseline, not as your usual full-day calorie target. |
| TDEE | Your estimated total daily energy expenditure after an activity factor is added to BMR. | Use it as a maintenance-calorie starting point before you plan for fat loss, maintenance, or lean gain. |
How this calculator works
- Your age, sex, height, and weight are used to estimate BMR with the Mifflin-St Jeor equation.
- Your selected activity level provides the multiplier used to estimate TDEE.
- The page shows your BMR, your TDEE, the multiplier used, and guidance on how to treat the result as a maintenance starting point.
- If you want goal-based intake targets after that, the next step is the calorie intake calculator.
Formula transparency
Default formula on this page
Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Why Mifflin-St Jeor is used
It is one of the most common adult predictive equations for resting energy expenditure and works well as a clear default for a public-facing calculator.
Advanced formula note
Other formulas such as Harris-Benedict and Katch-McArdle exist. Katch-McArdle can be more useful when lean-mass data is known, but this live tool stays simple by using one transparent default equation.
Activity level guide
| Level | Multiplier | Typical fit | Common mistake |
|---|---|---|---|
| Sedentary | 1.2 | Mostly seated work, low daily movement, little structured exercise | Choosing a higher level because of one or two hard workouts |
| Lightly active | 1.375 | Light movement or training 1 to 3 days per week | Counting occasional exercise as a full moderate routine |
| Moderately active | 1.55 | Consistent training 3 to 5 days per week or a generally active daily routine | Ignoring long seated workdays outside the gym |
| Very active | 1.725 | Hard training most days, active job, or both | Using this level without enough weekly training or movement volume |
| Extra active | 1.9 | High-volume training, sport, or very demanding physical work | Using the highest factor when recovery or routine is inconsistent |
If you are unsure, start one activity level lower and refine from actual progress. Activity overestimation is one of the most common reasons maintenance estimates feel wrong.
How to use your result
Use BMR for baseline context
BMR helps you understand your resting energy demand and why your body still burns calories even at full rest.
Use TDEE for maintenance planning
TDEE is the better maintenance starting point because it combines resting metabolism with a practical activity estimate.
Track before making large changes
Hold your intake and routine steady for 2 to 3 weeks, then compare weight trend, appetite, performance, and recovery before adjusting calories.
Limitations and accuracy note
- These numbers are estimates, not direct metabolic measurements.
- Daily movement outside exercise can shift your real maintenance calories more than you expect.
- Body composition, hormonal status, sleep, stress, illness, and routine changes can all affect real-world energy needs.
- Adults usually get the best results when calculator estimates are refined with trend data instead of treated as exact prescriptions.
References
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition. 1990;51(2):241-247.
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association. 2005;105(5):775-789.
- Energy-expenditure guidance consistently notes that predictive equations are starting estimates and work best when refined with real-world tracking, body-composition context, and routine review.
- Daily energy needs can drift with body size, activity, NEAT, training load, sleep, stress, and adherence, so calorie planning should be adjusted from trends rather than one isolated number.
BMR and TDEE calculator FAQ
What is the difference between BMR and TDEE?
BMR is the energy your body uses at full rest for basic functions such as breathing, circulation, and temperature control. TDEE adds daily movement and exercise on top of that resting baseline, so it is usually the more useful maintenance-calorie estimate.
Should I eat at my BMR or my TDEE?
For most adults, TDEE is the more practical maintenance starting point because it includes daily activity. BMR is a resting estimate, not a full-day intake target.
Which formula does this calculator use?
This calculator uses the Mifflin-St Jeor equation as its default BMR estimate because it is widely used for adult energy-expenditure estimation. Other formulas exist, but this page keeps the live tool simple and transparent.
Which activity level should I choose?
Choose the level that best matches your full weekly routine, not your hardest workout. If you are uncertain, it is usually safer to start one activity level lower and adjust from real-world tracking.
Why can my TDEE estimate feel too high or too low?
TDEE is a starting estimate, not a direct measurement. Activity overestimation, changes in daily movement, body composition, sleep, stress, and logging accuracy can all shift your real-world maintenance calories.
Is this the same as a calorie intake calculator?
No. This page focuses on metabolism estimation, resting energy, activity factors, and maintenance calories. The calorie intake calculator is the better next step when you want goal-based eating targets for fat loss, maintenance, or lean gain.
Can this tool replace medical advice or metabolic testing?
No. This page is an educational calculator. Pregnancy, eating disorders, thyroid disease, diabetes, recent rapid weight change, and other medical conditions can change how energy needs should be interpreted.