Most adults need between 1,600 and 3,000 calories per day to maintain their weight, depending on sex, age, and how active they are. That’s a wide range, which is why a single number never applies to everyone. Your actual maintenance calories depend on your body size, muscle mass, daily movement, and even what you eat.
General Calorie Ranges by Age and Activity
The Dietary Guidelines for Americans (2020–2025) provide estimated maintenance calories broken into three activity levels: sedentary, moderately active, and active. Sedentary means you only do the basic physical activity of daily living. Moderately active adds the equivalent of walking 1.5 to 3 miles per day. Active means walking more than 3 miles per day on top of your normal routine.
For adult men, the ranges look like this:
- Ages 21–25: 2,400 (sedentary) to 3,000 (active)
- Ages 31–40: 2,400 (sedentary) to 2,800–3,000 (active)
- Ages 41–50: 2,200 (sedentary) to 2,800 (active)
- Ages 51–60: 2,200 (sedentary) to 2,600–2,800 (active)
- Ages 61–75: 2,000 (sedentary) to 2,600 (active)
- Ages 76+: 2,000 (sedentary) to 2,400 (active)
For adult women:
- Ages 21–25: 2,000 (sedentary) to 2,400 (active)
- Ages 26–50: 1,800 (sedentary) to 2,200–2,400 (active)
- Ages 51–60: 1,600 (sedentary) to 2,200 (active)
- Ages 61+: 1,600 (sedentary) to 2,000 (active)
These are population-level estimates. A 6’2″ sedentary man will need more calories than a 5’6″ sedentary man of the same age. But these tables give you a reasonable starting point before you calculate anything more precise.
How to Calculate Your Personal Number
The most common approach is to estimate your resting metabolic rate (the calories your body burns just keeping you alive) and then multiply it by an activity factor. Two well-known formulas exist for that first step: the Harris-Benedict equation and the Mifflin-St. Jeor equation. The American Dietetic Association concluded that Mifflin-St. Jeor was more likely to land within 10% of your true resting metabolic rate, though subsequent research has found the Harris-Benedict equation performs just as well, and sometimes better, across diverse populations. Either one gets you in the right ballpark.
Once you have that resting number, you multiply by a physical activity level (PAL) factor. A PAL below 1.4 reflects someone who is basically inactive. A PAL above 1.6 is considered physically active. Most people with desk jobs who exercise a few times a week fall somewhere around 1.4 to 1.6. Elite endurance athletes can hit a PAL above 2.5, but that’s extreme.
A simpler shortcut: multiply your body weight in pounds by 14 to 16 if you’re lightly active, or by 16 to 18 if you exercise regularly. This gives a rough daily calorie estimate for maintenance. It’s less precise than the formula approach, but many people find it more practical as a starting point they can adjust from.
Why Men and Women Have Different Needs
Men typically burn about 23% more calories at rest than women, even after accounting for differences in muscle mass. The gap in the tables above (often 400 to 600 calories per day) reflects this. The main driver is body composition: men carry more lean tissue on average, and lean tissue is more metabolically expensive than fat. But hormonal and physiological differences also play a role independent of body size.
A pound of muscle burns roughly 5 to 7 calories per day at rest. That sounds modest, but the difference between someone with 30 extra pounds of muscle and someone without adds up to 150 to 210 extra calories burned daily, doing nothing. Your internal organs (brain, liver, heart, kidneys) are actually far more metabolically active than muscle, burning 15 to 40 times more energy per pound, but you can’t grow a bigger liver through training. Muscle is the one component of your resting metabolism you can meaningfully change.
The Huge Role of Daily Movement
Formal exercise gets most of the attention, but the calories you burn through non-exercise movement throughout the day (walking to the kitchen, fidgeting, standing, carrying groceries) can matter even more. Researchers call this non-exercise activity thermogenesis, or NEAT. According to Mayo Clinic researcher James Levine, who pioneered this area of study, NEAT can vary by up to 2,000 calories per day between two people of similar size.
That’s not a typo. Two people who weigh the same and do the same formal workouts can differ by 2,000 calories in daily burn, simply based on how much they move during the rest of their day. Studies comparing lean and obese sedentary people with similar jobs found that the obese group sat about two and a half hours more per day, while the lean group stood or walked more than two hours longer. If you sit at a desk all day and wonder why an online calculator’s number doesn’t match your reality, this is likely why.
Your Diet Composition Matters Too
Your body spends energy digesting food, a process called the thermic effect of food. Not all calories cost the same amount to process. Protein requires the most energy: your body uses 15 to 30% of protein calories just to digest and absorb them. Carbohydrates cost 5 to 10%. Fats cost almost nothing, at 0 to 3%.
This means two people eating the same total calories but different ratios of protein, carbs, and fat will have slightly different net energy available. Someone eating a high-protein diet effectively “loses” more calories to digestion. It’s not a dramatic difference (maybe 100 to 200 calories per day for a very high-protein diet), but it’s one more reason your maintenance number isn’t perfectly fixed.
Does Metabolism Slow With Age?
Less than you probably think, and later than you’d expect. A landmark 2021 study analyzing over 6,400 people found that metabolism stays remarkably stable from age 20 to about 60, regardless of sex. The common belief that your metabolism tanks in your 30s or 40s isn’t supported by the data. Weight gain during middle age is more likely driven by changes in eating habits and activity levels than by a metabolic slowdown.
After about age 60, metabolism does begin declining at roughly 0.7% per year, even beyond what’s explained by losing muscle mass. By age 90, total daily energy expenditure runs about 26% below that of middle-aged adults. So if you’re under 60, a sluggish metabolism probably isn’t the reason the scale is creeping up. If you’re over 60, a modest reduction in maintenance calories (visible in the tables above) is real and expected.
What Happens After Weight Loss
If you’ve recently lost a significant amount of weight, your maintenance calories will be lower than a formula predicts for someone who has always been at your current weight. This is partly straightforward: a smaller body burns fewer calories. But your body also appears to enter a conservation mode after weight loss, reducing energy expenditure beyond what the lost tissue alone would explain. Your resting metabolism dips, and you tend to burn fewer calories during movement as well.
This metabolic adaptation varies between individuals. For some people it’s minimal; for others it can mean burning a few hundred fewer calories per day than expected. It doesn’t make weight maintenance impossible, but it does mean you may need to be more deliberate about activity and portion sizes than someone who never gained the weight in the first place.
Finding Your Actual Maintenance Calories
Formulas and tables are estimates. The only way to find your true maintenance number is to track what you eat and what you weigh over two to three weeks. If your weight stays stable, you’ve found your maintenance intake. If it drifts up, you’re eating above maintenance. If it drifts down, you’re below.
Weigh yourself at the same time each day (morning, after using the bathroom) and look at the weekly average rather than any single day. Daily weight fluctuates by 2 to 4 pounds based on water, sodium, and food volume. The trend over 14 to 21 days tells the real story. Start with an estimate from the tables above or a calculator, eat consistently at that level, and adjust by 100 to 200 calories based on what the scale does. It’s not glamorous, but it’s the most reliable method available.