01
Estimate maintenance
Maintenance calories—or TDEE—are the estimated calories your body uses through resting metabolism, digestion, daily movement, and exercise.
Currently Serving Texas Residents Only (Florida, Colorado, Hawaii coming soon)
Currently Serving Texas Residents Only (Florida, Colorado, Hawaii coming soon)
Estimate maintenance calories, compare weight-loss targets, and see an approximate timeline built around your inputs.
For adults 18 and older. Results are estimates for education—not a diagnosis or individualized nutrition prescription.
Enter your current measurements, goal, and typical activity.
Your selected pace will appear here.
Goal: —
Static estimate; actual timing may differ.
Estimates will use the Mifflin–St Jeor equation unless body-fat percentage is added.
Explore provider-led weight loss support and personalized treatment options.
Get our Nutrition and Training Blueprints for practical help with meals, protein, strength training, movement, and recovery.
Enter your email to receive both Magnum Blueprints.
We’ll email a confirmation link. Confirm it to receive both guides. Unsubscribe anytime.
A calorie deficit means taking in less energy than your body uses over time. That difference can support weight loss, but the day-to-day scale never moves in a perfectly straight line.
Maintenance calories—or TDEE—are the estimated calories your body uses through resting metabolism, digestion, daily movement, and exercise.
Eating below estimated maintenance creates the mathematical deficit shown by this calculator. A smaller deficit generally changes the timeline more gradually.
Equations cannot see your exact metabolism or intake. Use average weight trends, energy, hunger, performance, and health context to evaluate the estimate.
The result combines an established resting-energy equation with your activity selection, then subtracts the deficit associated with your chosen weekly pace.
Mifflin–St Jeor uses age, sex, height, and weight. Optional body-fat data switches the calculation to Katch–McArdle.
Resting energy is multiplied by the selected activity factor to estimate total daily energy expenditure.
The selected pace represents approximately 250, 500, 750, or 1,000 calories per day.
The projected timeline uses the traditional 3,500-calorie-per-pound approximation. It is useful for comparison, but real weight change commonly slows or fluctuates as body weight, activity, water balance, and energy needs change.
When body-fat percentage is left blank, the calculator estimates resting energy from weight, height, age, and the selected sex coefficient.
Male: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Female: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Age and sex directly affect this version of the estimate.
This option estimates resting energy from calculated lean body mass.
Resting energy: 370 + (21.6 × lean mass in kg)
Lean mass: weight × (1 − body-fat percentage ÷ 100)
Age and sex do not enter this equation directly, and inaccurate body-fat estimates can materially change the result.
The resting-energy estimate is multiplied by the selected activity factor. These broad categories are planning shortcuts—not measurements of actual calorie burn.
| Activity selection | Multiplier |
|---|---|
| Sedentary · little exercise | 1.20 |
| Light · 1–3 days/week | 1.375 |
| Moderate · 3–5 days/week | 1.55 |
| Very active · 6–7 days/week | 1.725 |
| Extremely active · hard training/job | 1.90 |
The fastest mathematical option is not automatically the best personal target. The right pace should leave room for nutrition, training, recovery, and consistency.
A planned 250–500 calorie daily deficit can be easier to sustain and may leave more flexibility for adequate nutrition and training.
A planned 750–1,000 calorie daily deficit creates a faster mathematical timeline, but can be difficult or inappropriate depending on body size and health.
A deficit does not require eliminating entire food groups or trying to “burn off” every meal. The most workable approach usually combines a few modest changes you can repeat.
Choose a practical protein source at each meal, then add produce and other foods that fit your calorie and nutrition needs.
Vegetables, fruit, beans, and whole grains can add volume and help meals feel more substantial for their calorie content.
Sweetened drinks, alcohol, sauces, oils, and frequent bites can add energy without creating the fullness of a complete meal.
Consistent portions make it easier to evaluate what is working. Tracking can help temporarily, but it is not the only way to create structure.
Walking, planned exercise, active errands, and less sitting can raise expenditure without depending on punishing workouts.
Compare several weeks of average weight, intake, hunger, and performance. Make small changes when the trend does not match the plan.
“Too aggressive” means the calorie reduction is creating persistent symptoms, compromising normal function or recovery, or producing weight loss substantially faster than intended. One isolated hard day is different from a pattern that continues.
Feeling faint, unusually weak, or unable to complete normal daily activities deserves prompt attention.
A plan that dominates your thoughts or feels impossible to control may need more support and a different approach.
A notable drop in strength, endurance, or recovery can signal that energy intake and training demand are poorly matched.
Worsening sleep, irritability, or a sustained decline in wellbeing are reasons to reassess the plan.
Changes in menstrual function can have multiple causes and warrant individualized medical guidance.
Weight loss that is much faster than planned—or continues without trying—should be discussed with a clinician.
A calculator can estimate energy needs, but it cannot verify logged intake or predict short-term scale changes. A slower-than-expected trend can reflect the estimate, tracking differences, water shifts, adherence, medications, or changing energy needs.
Broad categories cannot capture every workout, step, job, or change in routine.
Portion estimates, labels, restaurant meals, and missed items can change logged intake.
Hydration, sodium, carbohydrate intake, and digestion can temporarily move scale weight.
Energy needs can change as weight drops and the body adapts during sustained weight loss.
One or two weigh-ins can be dominated by normal fluctuation rather than the underlying trend.
Medications, medical conditions, pregnancy, and eating-disorder concerns require individualized care.
Review comparable weigh-ins as a multi-week trend, check whether portions and activity match the inputs, and recalculate after meaningful weight or routine changes. Seek qualified guidance if the target feels difficult to sustain or symptoms develop.
A calorie deficit occurs when average calorie intake is lower than the energy your body uses over time. The size and consistency of that difference influence the mathematical weight-loss estimate.
It estimates resting energy with Mifflin–St Jeor, or Katch–McArdle when body-fat percentage is entered, then applies an activity factor to estimate maintenance calories. Your selected deficit is subtracted from that estimate.
No. It reflects the traditional 3,500-calorie approximation. Weight change is not perfectly linear, and real outcomes can differ because energy needs, adherence, water balance, activity, and metabolism change over time.
The calculator estimates maintenance calories from your measurements and activity, then subtracts the deficit associated with the pace you select. Use the displayed daily target as a starting estimate—not a prescription. Individual needs and real-world results vary, and targets below 1,000 calories per day are not displayed.
Exercise can increase energy expenditure, while nutrition changes can reduce intake. Many people use a combination of food choices, structured exercise, and daily movement rather than relying on one lever alone.
No. It is optional. If you add it, the calculator uses estimated lean mass with Katch–McArdle, but inaccurate body-fat measurements can make that estimate less useful.
For a mathematical target below 1,000 calories per day, the calculator displays “Not appropriate” and withholds the timeline for that pace. Select a slower rate and seek individualized professional guidance.
The displayed timeline is a static baseline projection based on the selected weekly rate. Scale weight fluctuates and energy expenditure can change during weight loss, so actual timing may be shorter or longer.
The estimate, food tracking differences, water shifts, adherence, activity, medications, and changing energy needs can obscure the expected trend. Review comparable weigh-ins over multiple weeks and recalculate after meaningful changes.
Recalculate after a meaningful change in weight, activity, training schedule, or daily routine. Compare estimates with multi-week averages rather than reacting to a single weigh-in.
It is intended for adults 18 and older. Minors, pregnant or breastfeeding individuals, people with eating-disorder concerns, and anyone with a condition affecting nutrition or metabolism should seek individualized professional guidance.
The calculator uses established energy equations and standard activity factors to create an educational estimate. It also explains why a fixed calorie-to-weight conversion should not be treated as a guaranteed forecast.
No crash diets. No guessing games. Connect with a Magnum Health provider and explore a personalized plan built around your goals.
This calculator and page are for general educational purposes only and are not medical advice, diagnosis, or a substitute for professional care. The results are mathematical estimates and do not establish an appropriate calorie intake, expected rate of weight loss, or treatment eligibility. Services and prescriptions, when appropriate, require evaluation by a licensed clinician.