How to Calculate Maintenance Calories (and Check the Number)

To calculate maintenance calories, estimate the calories your body burns at rest with the Mifflin-St Jeor equation, multiply that by an activity factor for how much you move and train, and then check the result against your actual weight trend over a few weeks.

Maintenance calories are the calories you can eat each day without gaining or losing weight. Every diet number builds on this one: a cut is a set amount below it, a bulk a set amount above it. So it is worth getting roughly right, and worth knowing how rough it is.

Step 1: Estimate your resting calories

Your resting energy expenditure is what your body burns just to keep running, before any activity. The most widely used way to estimate it is the Mifflin-St Jeor equation, published in the American Journal of Clinical Nutrition in 1990. It was built from 498 healthy adults, men and women aged 19 to 78, both normal-weight and with obesity, whose resting energy use was measured in a lab.

With weight in kilograms, height in centimeters, and age in years:

• Men: 10 × weight + 6.25 × height − 5 × age + 5
• Women: 10 × weight + 6.25 × height − 5 × age − 161

To convert, divide pounds by 2.2 for kilograms and multiply inches by 2.54 for centimeters.

Why this formula? A systematic review in the Journal of the American Dietetic Association compared the four equations most used in clinical practice (Harris-Benedict, Mifflin-St Jeor, Owen, and WHO/FAO/UNU). Mifflin-St Jeor was the most reliable: it predicted resting metabolic rate within 10% of the measured value in more people, with and without obesity, than any of the others. The original Mifflin study also found the older Harris-Benedict equations overestimated measured resting energy by about 5%.

Step 2: Multiply by an activity factor

Resting calories leave out everything you do in a day. The usual next step is to multiply them by an activity factor. These are the five levels Metriq uses:

The most common mistake here is picking a level that is too high. These factors already include your workouts, so someone who lifts four days a week belongs in "moderately active", not "very active". In the example below, picking one level too high would add about 310 calories a day that he doesn't actually burn.

A worked example

Take a 30-year-old man who weighs 180 lb (about 81.6 kg), is 5 feet 10 inches tall (about 178 cm), and lifts four days a week.

1. Resting calories: 10 × 81.6 + 6.25 × 178 − 5 × 30 + 5 = about 1,784 calories a day.
2. Activity factor: four training days puts him at moderately active, 1.55.
3. Maintenance estimate: 1,784 × 1.55 = about 2,765 calories a day.

That is a starting estimate, not a measurement.

Step 3: Check the estimate against your weight

Even the best formula is a population average. The same review that favored Mifflin-St Jeor warned that it still has noteworthy errors when applied to individuals, and that older adults and some ethnic groups were underrepresented in the studies behind these equations. Your real maintenance could sit above or below the number you calculated.

The practical check is your own weight trend:

1. Eat close to your estimate for two to three weeks, and log it honestly.
2. Weigh in under the same conditions each time, and look at the trend, not single readings. Our guide on how often to weigh yourself covers how.
3. Read the trend. If your weight holds steady, your estimate is close. If it drifts up, your maintenance is lower than you calculated; if it drifts down, it is higher. Adjust in small steps and check again.

Your maintenance number moves

Maintenance is not fixed. It depends on your weight, so it falls as you lose weight and rises as you gain. Research from the US National Institutes of Health on how body weight responds to changes in calorie intake models energy expenditure adapting during weight loss and finds that body weight responds slowly to a change in how much you eat. The NIH turned that research into a free Body Weight Planner if you want to model it.

This is the usual reason for a stall partway through a diet. If your weight has stopped moving, recalculating maintenance at your current weight is the first thing to do; our guide to a weight loss plateau walks through the rest.

From maintenance to a target

Once you have a maintenance number you trust, your goal sets the rest:

• To lose fat, eat a moderate amount below it. Our guide to macros for cutting covers how big a deficit and how to split it into protein, fat, and carbs.
• To build muscle, eat a modest amount above it. Our guide to a lean bulk covers how big a surplus.
• To recomp, stay close to it while you train hard.

Where Metriq fits

Metriq does this calculation for you. It estimates your resting calories with the Mifflin-St Jeor equation and multiplies them by one of the five activity levels above, which are described by how often you train. Your calorie target is then a percentage of that maintenance estimate: 15, 20, or 25% below it on a fat-loss plan, 5, 10, or 15% above it on a muscle-gain plan, and within 5% either side on a recomp plan. When you log a newer weight at your weekly check-in, the estimate is recalculated from your current weight rather than the weight you started at. See My Numbers →

Frequently asked questions

What is the best formula to calculate maintenance calories?

For resting calories, a systematic review found the Mifflin-St Jeor equation the most reliable of the four common clinical equations, predicting within 10% of measured resting metabolic rate in more people than the others. Multiply its result by an activity factor to estimate maintenance.

How do I calculate maintenance calories from BMR?

Multiply your BMR (resting calories) by an activity factor: about 1.2 if you are sedentary, 1.375 if lightly active, 1.55 if you exercise 3 to 5 days a week, 1.725 for hard exercise 6 to 7 days a week, and 1.9 for daily hard training plus a physical job.

Is the maintenance calorie formula different for men and women?

Yes, slightly. In the Mifflin-St Jeor equation, men add 5 at the end and women subtract 161. The weight, height, and age parts are the same.

How accurate are maintenance calorie calculators?

They are a good starting point, not a measurement. Even the most reliable equation can be off for an individual, so check your estimate against your weight trend over two to three weeks and adjust.

Do maintenance calories change when you lose weight?

Yes. A lighter body burns fewer calories, so maintenance drops as you lose weight. Recalculate it with your current weight every so often, especially if your progress stalls.

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This article is educational and general in nature. It isn't personalized medical or nutrition advice. Talk with a qualified professional before starting or changing a diet or training program.

Related: Macros for Cutting: How to Set Protein, Fat, and Carbs · Weight Loss Plateau: Why It Happens and How to Break It · Back to the blog

Sources

• Mifflin-St Jeor equation; 498 healthy adults (247 women, 251 men) aged 19 to 78, normal-weight and obese, resting energy measured by indirect calorimetry; simplified equations for men (+5) and women (−161); Harris-Benedict overestimated measured resting energy by 5% (Mifflin, St Jeor et al., 1990, American Journal of Clinical Nutrition): pubmed.ncbi.nlm.nih.gov/2305711
• Mifflin-St Jeor the most reliable of Harris-Benedict, Mifflin-St Jeor, Owen, and WHO/FAO/UNU, predicting within 10% of measured resting metabolic rate in more nonobese and obese people than any other; noteworthy errors for individuals; older adults and US ethnic minorities underrepresented (Frankenfield, Roth-Yousey & Compher, 2005, Journal of the American Dietetic Association): pubmed.ncbi.nlm.nih.gov/15883556
• Energy expenditure adapts during weight loss and body weight responds slowly to a change in intake; web-based simulator (Hall et al., 2011, The Lancet, NIDDK): pubmed.ncbi.nlm.nih.gov/21872751
• NIDDK Body Weight Planner: niddk.nih.gov/bwp