The number of calories you need each day depends on your age, sex, and how active you are. For a rough answer: most adult women need between 1,600 and 2,400 calories per day, and most adult men need between 2,000 and 3,000. But those ranges shift significantly across the lifespan, peaking during adolescence and gradually declining after age 60. The tables and details below will help you find a more specific number.
Daily Calorie Needs for Females by Age
These estimates come from the 2020-2025 Dietary Guidelines for Americans, published by the USDA. “Sedentary” means you only do the basic physical activity of daily living. “Moderately active” is roughly equivalent to walking 1.5 to 3 miles per day on top of that. “Active” means walking more than 3 miles per day or doing equivalent exercise.
- Ages 2-3: 1,000 to 1,400 calories
- Ages 4-8: 1,200 to 1,800 calories
- Ages 9-13: 1,400 to 2,200 calories
- Ages 14-18: 1,800 to 2,400 calories
- Ages 19-25: 2,000 (sedentary) to 2,400 (active)
- Ages 26-50: 1,800 (sedentary) to 2,200 (active)
- Ages 51-60: 1,600 (sedentary) to 2,200 (active)
- Ages 61-76+: 1,600 (sedentary) to 2,000 (active)
Female calorie needs peak during the late teens and early twenties, then begin a slow decline. By your fifties, sedentary needs drop to around 1,600 calories, a reduction of about 400 calories from where they were in your twenties. The decline is steepest for those who aren’t physically active.
Daily Calorie Needs for Males by Age
- Ages 2-3: 1,000 to 1,400 calories
- Ages 4-8: 1,200 to 2,000 calories
- Ages 9-13: 1,600 to 2,600 calories
- Ages 14-18: 2,000 to 3,200 calories
- Ages 19-25: 2,400 (sedentary) to 3,000 (active)
- Ages 26-45: 2,200 to 2,400 (sedentary), up to 2,800 to 3,000 (active)
- Ages 46-65: 2,000 to 2,200 (sedentary), up to 2,600 to 2,800 (active)
- Ages 66-76+: 2,000 (sedentary) to 2,400 to 2,600 (active)
Male calorie needs peak dramatically during the mid-teens. Active 16- to 18-year-old boys may need up to 3,200 calories a day, the highest recommendation on the entire chart. After about age 40, needs taper by a few hundred calories per decade for sedentary individuals, while staying relatively higher for those who remain physically active.
Why Teens Need the Most Calories
The body demands more calories during early adolescence than at any other time of life. A surge in appetite typically hits around age 10 in girls and age 12 in boys, foreshadowing the growth spurt of puberty. During this phase, the body is building bone, adding muscle, and going through rapid hormonal changes that all require energy. On average, adolescent boys need about 2,800 calories per day and adolescent girls about 2,200, though active teens can need considerably more.
These elevated needs are temporary. Once growth slows in the late teens, calorie requirements settle into adult ranges. Eating too little during this window can interfere with development, so this is not an ideal time for restrictive dieting.
What Happens to Your Metabolism After 60
A large 2021 study published in Science overturned some long-held assumptions about metabolism and aging. The key finding: your metabolic rate stays remarkably stable from age 20 all the way through age 60, regardless of sex. The middle-age “metabolism slowdown” that many people blame for weight gain doesn’t show up in the data. Weight gain during those decades is more likely driven by changes in eating habits and reduced physical activity than by a slower metabolism.
The real metabolic shift begins around age 60. After that point, both resting metabolism and total energy expenditure decline by about 0.7% per year, even after accounting for changes in body size. By age 90, total energy expenditure is roughly 26% below that of middle-aged adults. This decline appears to reflect organ-level metabolic changes, not just loss of muscle mass. It means older adults genuinely need fewer calories, but the calories they do eat need to be more nutrient-dense to cover the same nutritional requirements in a smaller calorie budget.
How Activity Level Changes Your Number
Activity level is the single biggest variable you can control. Looking at the USDA data, the gap between a sedentary and active person of the same age and sex can be 400 to 800 calories per day. For a 35-year-old man, that’s the difference between 2,400 and 3,000 calories. For a 35-year-old woman, it’s 1,800 versus 2,200.
The definitions are more modest than most people expect. You qualify as “moderately active” by walking 1.5 to 3 miles a day at a normal pace, on top of your regular daily tasks. “Active” means more than 3 miles of walking per day or the exercise equivalent. If you sit at a desk all day and don’t exercise, you’re sedentary, even if you feel busy. Researchers use a ratio called the physical activity level (PAL), which compares your total energy expenditure to your resting metabolic rate. A PAL below 1.4 is classified as inactive, while above 1.6 counts as physically active. Elite athletes can reach a PAL above 2.5.
Calorie Needs During Pregnancy
Pregnancy increases calorie needs, but not as dramatically as many people assume. During the first trimester, most normal-weight women need about 1,800 calories a day, which is often no increase at all over baseline. The second trimester bumps that to about 2,200 calories, and the third trimester to about 2,400. That works out to roughly 300 extra calories per day over a typical non-pregnant intake, or about the equivalent of a large banana with a tablespoon of peanut butter.
The old advice to “eat for two” significantly overstates the actual increase. Eating well beyond these ranges during pregnancy increases the risk of complications. What matters more than quantity is the quality of those calories, particularly getting enough folate, iron, calcium, and protein.
How to Estimate Your Personal Number
The tables above give population-level estimates, but your individual needs depend on your specific weight, height, and body composition. The most widely recommended formula for estimating your resting metabolic rate is the Mifflin-St Jeor equation. A systematic review in the Journal of the American Dietetic Association found it was more accurate than competing formulas, predicting resting metabolic rate within 10% of measured values in more people than any other equation tested.
The formula uses your weight in kilograms, height in centimeters, and age in years. You can find Mifflin-St Jeor calculators online that do the math for you. Once you have your resting number, you multiply it by an activity factor (typically 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, and 1.725 for very active) to estimate your total daily calorie needs.
Keep in mind that no formula is perfect. The Mifflin-St Jeor equation was developed and validated primarily in younger, non-Hispanic white populations. It may be less accurate for older adults and for people from other ethnic backgrounds. Your actual calorie needs also shift day to day based on sleep, stress, illness, and how much you moved. The USDA tables and calculators are useful starting points, but your body weight over time is the most honest feedback. If your weight is stable, you’re eating roughly the right amount. If it’s trending in a direction you don’t want, adjust by 200 to 300 calories and give it a few weeks.
Calorie Needs for Adults Over 70
Older adults face a nutritional paradox: they need fewer calories but the same (or higher) amounts of most nutrients. A sedentary woman over 70 needs only about 1,600 calories, and a sedentary man about 2,000. That’s a tight budget for fitting in enough protein, calcium, vitamin D, and B12.
Protein deserves special attention. The general adult recommendation is about 0.36 grams of protein per pound of body weight per day, but many experts argue older adults benefit from more, particularly to prevent the gradual loss of muscle mass that accelerates after 60. Spreading protein intake evenly across meals, rather than loading it all into dinner, appears to be more effective for maintaining muscle. Pairing adequate protein with resistance exercise produces the most improvement in muscle mass and strength, even well into the seventies and eighties.