Most adults burn between 1,600 and 2,400 calories per day, though the actual number varies widely based on your size, age, sex, and how much you move. A small, sedentary woman might sit closer to 1,600, while a large, active man could burn well over 3,000. Your daily calorie burn isn’t one number but the sum of several different processes happening in your body around the clock.
The Three Parts of Your Daily Burn
Your total daily energy expenditure breaks down into three main components, and the biggest one has nothing to do with exercise. Your resting metabolism, the energy your body uses just to keep you alive (breathing, circulating blood, maintaining body temperature, repairing cells), accounts for 60 to 70 percent of everything you burn. For someone who burns 2,000 calories a day, that’s roughly 1,200 to 1,400 calories spent before they even get out of bed.
Physical activity makes up the second-largest share, ranging from about 15 percent in sedentary people up to 50 percent in highly active individuals. This includes both structured exercise and all the smaller movements you make throughout the day: walking to the kitchen, fidgeting, standing up, carrying groceries. The third component is the thermic effect of food, the energy your body spends digesting what you eat, which accounts for about 10 percent of your daily total.
How to Estimate Your Resting Metabolism
The most widely recommended formula for estimating your resting metabolic rate is the Mifflin-St Jeor equation. A systematic review found it predicted resting metabolism within 10 percent of the actual measured value more often than any competing formula, and with the narrowest margin of error. Here’s how it works:
- Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
For a 35-year-old woman who is 5’5″ (165 cm) and weighs 150 pounds (68 kg), that comes out to roughly 1,374 calories at rest. A 35-year-old man at 5’10” (178 cm) and 180 pounds (82 kg) gets about 1,748 calories. These numbers represent the bare minimum your body needs to function, before any movement or digestion is factored in.
Turning Your Resting Rate Into a Full-Day Estimate
To get from your resting metabolism to your total daily burn, you multiply by an activity factor. These multipliers are based on standardized Physical Activity Level (PAL) values:
- Sedentary (desk job, little movement): multiply by 1.2
- Lightly active (some walking, light exercise 1 to 3 days a week): multiply by 1.4 to 1.5
- Moderately active (exercise 3 to 5 days a week): multiply by 1.6 to 1.7
- Very active (hard exercise 6 to 7 days a week or physical job): multiply by 1.9 or higher
Using the woman from the earlier example: if she’s lightly active, her estimated daily burn is about 1,374 × 1.4, or roughly 1,924 calories. If she’s sedentary, it drops closer to 1,649. These are estimates, not exact figures. Individual variation of 10 to 15 percent in either direction is normal, even between two people of the same size, age, and activity level.
Why Movement Outside the Gym Matters So Much
Formal exercise gets most of the attention, but the calories you burn through everyday movement (called non-exercise activity thermogenesis, or NEAT) can actually make a bigger difference. Simply standing increases your energy expenditure 10 to 20 percent above resting levels. Walking doubles or even triples it. Activities like pacing while on the phone, taking the stairs, cooking, or cleaning all contribute.
The gap between a fidgety, on-your-feet person and someone who sits most of the day is substantial. Research has shown that adopting more active daily habits, without any structured exercise, can increase your burn by roughly 350 calories per day. That’s the equivalent of a 45-minute jog, achieved just by moving more in your normal routine.
What Your Food Choices Add to the Burn
Your body doesn’t absorb food for free. Digesting, absorbing, and processing nutrients requires energy, and different macronutrients cost different amounts. Protein is the most expensive to process: your body uses 20 to 30 percent of the calories in protein just to digest it. Carbohydrates cost 5 to 10 percent, and fat costs almost nothing at 0 to 3 percent.
In practical terms, if you eat 200 calories of chicken breast, your body spends 40 to 60 of those calories on digestion alone. The same 200 calories from butter costs your body only about 6 calories to process. This is one reason higher-protein diets tend to have a slight metabolic edge, though the overall difference in daily calorie burn from food composition alone is modest.
How Age, Sex, and Body Composition Shift the Number
Men typically have a higher resting metabolism than women, roughly 50 percent higher on average. But that gap almost entirely disappears when you account for body size and muscle mass. The real driver is how much lean tissue you carry, not your sex by itself. Each pound of muscle burns about 6 calories per day at rest, compared to just 2 calories per pound of fat. The old claim that a pound of muscle burns 50 calories a day is a myth, but the threefold difference between muscle and fat still adds up across your whole body.
Age plays a role too, though not in the way most people assume. A landmark study published in Science that tracked over 6,400 people using precise isotopic measurements found that metabolism holds remarkably steady throughout adulthood. The meaningful decline doesn’t begin until around age 60, after which total energy expenditure drops by about 0.7 percent per year. By the nineties, daily burn is roughly 26 percent below that of middle-aged adults. The “slowing metabolism” that people blame in their thirties and forties is more likely explained by gradual loss of muscle and reduced physical activity than by any inherent metabolic shift.
Why Your Estimate Might Be Off
All formulas have limits. The Mifflin-St Jeor equation was developed and validated primarily in white, younger to middle-aged adults. Its accuracy drops for older adults and for people from underrepresented ethnic groups. People with significantly more or less muscle than average for their height and weight will also get skewed results, since the formula can’t directly account for body composition.
Fitness trackers and smartwatches add another layer of estimation on top of these formulas. They can be useful for spotting trends, like whether you’re more active on weekdays than weekends, but their calorie counts are often off by 20 percent or more for any given day. If you’re using your daily burn to guide weight loss, treat the number as a starting point. Track your weight over two to three weeks and adjust your intake based on what actually happens on the scale, rather than trusting any single calculation.