How Do You Estimate Your Maintenance Calories?

Maintenance calories are the amount of energy you need to keep body weight roughly stable. You cannot measure it at home, but you can estimate it well enough to plan your eating and then correct the estimate with real data. The method has two parts: a starting figure from a formula, and a refinement based on how your weight changes over several weeks.

Start with an equation

Predictive equations such as Mifflin-St Jeor estimate resting energy use from body weight, height, age and sex. Resting energy use makes up the largest share of daily energy expenditure for most people, and body size and fat-free mass are its main drivers. Multiply the resting estimate by an activity factor that reflects your typical week, including training, daily walking and work. Be honest here. Many people overestimate how active they are, which inflates their maintenance figure.

Why the first number can be off

Equations are built from averages across groups of people, so they can be meaningfully wrong for any one individual. Everyday movement such as fidgeting and walking around varies a lot between people and between days. Food tracking adds more error, because database entries are estimates and self-reported intake is often under-reported. It helps to treat the equation as a hypothesis rather than a fact.

Energy use can also shift during a diet. Prolonged calorie restriction can lower energy expenditure more than body size alone would predict, and the size of this effect varies from person to person. That is one reason a number that worked in January may need revisiting by spring.

Use your own trend to refine it

Eat close to your estimated figure for two to four weeks, weigh yourself under similar conditions on most days, and look at weekly averages rather than single readings. Water, digestion and salt can move the scale by a noticeable amount in one day. If the weekly average stays flat, your intake is close to maintenance. If it rises steadily, your intake is above your real maintenance, and if it falls, it is below. Adjust in small steps and check again. Consistency over several weeks matters more than precision on any one day.

Apply the number to your goal

Once you have a working maintenance figure, a moderate deficit or surplus lets you aim for a slow, steady change in weight. Avoid very large cuts. Extreme restriction is hard to sustain and tends to work against training and recovery. Revisit your estimate when your body weight changes meaningfully or your activity changes, because maintenance moves with body size.

Takeaway

Estimate maintenance with a formula, be realistic about your activity, and then let two to four weeks of weight trends settle the answer. If a medical condition or past difficulty with eating makes calorie targets a concern, a registered dietitian or doctor can help you set a plan that suits you.