Your caloric maintenance level, often called Total Daily Energy Expenditure (TDEE), is the number of calories you burn in a full day. To calculate it, you estimate your Basal Metabolic Rate (BMR) using a formula based on your weight, height, age, and sex, then multiply that number by an activity factor. For most people, this produces an estimate within about 10% of their true maintenance calories.
Step 1: Estimate Your Basal Metabolic Rate
Your BMR is the energy your body uses just to keep you alive: breathing, circulating blood, maintaining body temperature, and running your organs. It typically accounts for 60 to 70% of your total daily calorie burn. The most widely recommended formula for estimating it is the Mifflin-St Jeor equation, which the Academy of Nutrition and Dietetics considers the best starting point for healthy adults.
The Mifflin-St Jeor equations use weight in kilograms, height in centimeters, and age in years:
- Men: BMR = (9.99 × weight) + (6.25 × height) − (4.92 × age) + 5
- Women: BMR = (9.99 × weight) + (6.25 × height) − (4.92 × age) − 161
To convert your measurements: multiply your weight in pounds by 0.4536 to get kilograms, and multiply your height in inches by 2.54 to get centimeters.
As a quick example, a 30-year-old man who weighs 180 pounds (81.6 kg) and stands 5’10” (177.8 cm) would calculate: (9.99 × 81.6) + (6.25 × 177.8) − (4.92 × 30) + 5 = roughly 1,780 calories per day at rest.
Step 2: Apply Your Activity Multiplier
Your BMR only reflects what you’d burn lying still all day. To get your actual maintenance calories, multiply your BMR by a Physical Activity Level (PAL) factor that reflects how much you move:
- Sedentary (desk job, little to no exercise): BMR × 1.2
- Lightly active (light exercise 1–3 days per week): BMR × 1.375
- Moderately active (moderate exercise 3–5 days per week): BMR × 1.55
- Very active (heavy exercise 6–7 days per week): BMR × 1.725
- Extremely active (intense training twice daily or hard labor job): BMR × 1.9
Using the example above, if that 30-year-old man exercises moderately three to five days a week, his estimated maintenance would be 1,780 × 1.55 = roughly 2,760 calories per day. That’s the number he’d eat to neither gain nor lose weight over time.
Most people overestimate their activity level. If you work a desk job and hit the gym three times a week for 45 minutes, “lightly active” is more honest than “moderately active.” Starting with a lower multiplier and adjusting upward based on real-world results will get you to an accurate number faster.
An Alternative Formula for Muscular or Lean People
The Mifflin-St Jeor equation uses total body weight, which means it doesn’t distinguish between muscle and fat. Since lean tissue burns significantly more energy than fat tissue, a person with an above-average amount of muscle mass will get a low estimate from standard formulas. The Katch-McArdle equation solves this by using lean body mass instead:
BMR = 370 + (21.6 × lean body mass in kg)
To use this, you need a reasonable estimate of your body fat percentage. Subtract your fat mass from your total weight to get lean body mass. If you weigh 200 pounds at 15% body fat, your lean mass is 170 pounds, or about 77 kg. That gives a BMR of 370 + (21.6 × 77) = roughly 2,033 calories. You’d then apply the same activity multipliers from Step 2.
This formula works equally for men and women because it relies on lean mass rather than sex-based averages. The tricky part is getting an accurate body fat estimate. DEXA scans and hydrostatic weighing are the most reliable methods, though even a good set of skinfold calipers gets close enough for this calculation.
How Accurate Are These Formulas?
Clinical studies comparing the Mifflin-St Jeor equation to actual metabolic measurements found it lands within 10% of the true value for about 82% of non-obese adults. That’s better than any other widely used formula. However, accuracy drops for people with obesity, falling to about 75%. The equation showed essentially no systematic bias in healthy adults, meaning it’s not consistently too high or too low.
A 10% margin of error on a 2,500-calorie estimate means your real maintenance could be anywhere from 2,250 to 2,750. That’s a meaningful range if you’re trying to lose or gain weight precisely, which is why formulas are best treated as a starting point rather than a final answer.
What Makes Your Maintenance Calories Unique
No formula can perfectly capture individual variation because several biological factors shift your calorie burn in ways that are hard to measure from the outside.
Age steadily lowers your BMR, primarily through muscle loss but also through hormonal and neurological changes. A person at 50 burns noticeably fewer calories at rest than they did at 25, even at the same weight. Body size also matters beyond what the formulas capture: more tissue and more cells require more energy to maintain, which is why taller people with larger frames tend to have higher maintenance levels than the equations predict.
One of the biggest hidden variables is non-exercise activity thermogenesis, or NEAT. This covers everything from fidgeting and pacing to standing while you work and walking to the kitchen. Research from the Mayo Clinic found that NEAT can differ by up to 2,000 calories per day between two people of similar size. That’s an enormous gap, and it explains why some people seem to eat freely without gaining weight while others feel like they gain weight easily. Your NEAT level is partly genetic and partly habitual, and it’s not something any formula accounts for.
The energy your body spends digesting food also plays a role. Protein costs the most to process, burning 15 to 30% of its calories during digestion. Carbohydrates cost 5 to 10%, and fats just 0 to 3%. This means two people eating the same total calories but different macronutrient ratios will end up with slightly different net energy. A high-protein diet effectively lowers your usable calorie intake by a small but real amount.
Why Maintenance Calories Change After Weight Loss
If you’ve recently lost a significant amount of weight, your maintenance calories will be lower than any formula predicts for your new weight. This phenomenon, called metabolic adaptation, means your body temporarily burns less energy than expected. Research published in the American Journal of Clinical Nutrition measured this effect at roughly 50 fewer calories per day on average after weight loss. That’s modest, not the dramatic “starvation mode” some people fear.
More encouraging: the same study found that this adaptation faded over time. In women tracked for two years after weight loss, the metabolic slowdown was no longer statistically significant by the one-year mark. Your metabolism does dip temporarily, but it largely recovers if you maintain your new weight.
How to Refine Your Estimate With Real Data
The most reliable way to find your true maintenance calories is to use a formula as your starting point, then track what actually happens. Eat at your calculated maintenance level for two to three weeks while weighing yourself daily and averaging the numbers weekly. If your weight stays stable, you’ve found your maintenance. If you’re gaining, drop by 100 to 200 calories. If you’re losing, add the same amount.
Daily weight fluctuations from water retention, sodium intake, and digestive contents can easily mask or fake a trend over a few days. This is why weekly averages matter more than any single weigh-in. Give the process at least two full weeks before making adjustments, and keep your activity level and food tracking consistent during that window. The formula gets you in the neighborhood. Tracking gets you to the actual address.