What maintenance calories mean
Maintenance calories are an estimate of daily energy intake that would match total daily energy expenditure and therefore tend to keep body weight stable over time. The idea is an energy balance, not a promise that weight will be identical every morning. Water, glycogen, food in the digestive tract, menstrual cycle changes and measurement conditions can move scale weight even when longer-term energy intake is near maintenance.
Two-step calculation
The calculator first estimates resting energy expenditure with the commonly used Mifflin–St Jeor equation. It then multiplies that baseline by a broad activity factor:
BMR and resting energy expenditure are closely related terms, but a predictive equation is not the same as a laboratory measurement. The final TDEE also includes daily movement, exercise and the energy used to process food.
Mifflin–St Jeor formula
The OfficeCalculator tool uses the widely used rounded form, with weight in kilograms, height in centimeters and age in years:
Female equation: BMR = 10W + 6.25H − 5A − 161
W is weight in kilograms, H is height in centimeters and A is age in years. The constant differs between the two equation groups. The original 1990 paper reported coefficients with slightly more precision; rounded versions are common in consumer calculations, so small differences between calculators are expected.
Activity factors
Typical calculator choices run from about 1.2 for sedentary activity to about 1.9 for very high activity. These labels are broad assumptions, not measurements. A desk worker who trains hard several days per week may not fit neatly into a label, and two people choosing “moderately active” can have very different step counts, work demands and training volume.
When uncertain, calculate two adjacent activity levels and treat the range as a sensitivity check. Do not choose a higher multiplier merely because it produces a preferred intake.
Worked maintenance-calorie example
For a 35-year-old man at 80 kg and 180 cm, the rounded equation gives:
Using a 1.55 moderate-activity factor gives 1,755 × 1.55 = 2,720.25, displayed as roughly 2,720 kcal/day. This is a model-based starting estimate. It is not a guarantee that 2,720 kcal will maintain this individual’s weight.
Use observed trends to refine the estimate
If it is appropriate and safe to track intake and weight, use consistent conditions over several weeks rather than adjusting from one day. Compare average intake with a rolling weight trend. If the trend is broadly stable, observed intake may be close to current maintenance. If it moves consistently, the calculator estimate, activity assumption or food tracking may need revision.
Maintenance is not fixed forever. Body weight, activity, training, illness, sleep, medications, pregnancy, breastfeeding, aging and environmental conditions can change energy needs. A value estimated today may need recalculation later.
Maintenance calories versus a deficit or surplus
A deficit is intake below estimated maintenance; a surplus is above it. Do not assume that a calculated deficit maps perfectly to a fixed amount of weekly weight change. Energy expenditure adapts, measurements are imperfect and short-term weight contains large non-fat fluctuations. Use the Calorie Deficit Calculator only as a planning scenario, not a medical instruction.
Who should not rely on a general adult formula
This adult estimator is not designed for children or teens, pregnancy, breastfeeding, eating-disorder treatment, serious illness or individualized sports nutrition. People with medical conditions, significant unintentional weight change or a history of disordered eating should seek qualified professional advice rather than using a generic calorie target.
Research source
The equation originates from Mifflin and colleagues’ 1990 study, A new predictive equation for resting energy expenditure in healthy individuals. It predicts resting expenditure from population data; it does not directly measure an individual’s TDEE.
Common mistakes
- Confusing BMR with total daily expenditure.
- Selecting an activity factor from aspiration rather than typical activity.
- Mixing pounds with a kilograms formula or inches with centimeters.
- Treating a calculated value as exact to the last calorie.
- Reacting to one day of scale weight instead of a longer trend.
- Applying an adult formula to children, pregnancy or clinical nutrition.
Frequently asked questions
Are maintenance calories the same as TDEE?
In consumer calculators, maintenance calories usually mean the estimated intake matching TDEE.
Is BMR my maintenance intake?
No. BMR estimates resting needs. Maintenance estimates include activity and other daily expenditure.
Which activity level should I choose?
Choose the label that best describes typical weeks, compare adjacent levels if uncertain and refine using safe, longer-term observations.
Why do calculators disagree?
They may use different equations, coefficient rounding, unit conversions or activity multipliers.