To maintain 150 pounds, most moderately active adults need roughly 2,250 calories per day. That number comes from a simple formula Harvard Health recommends: multiply your weight by 15. But your actual maintenance calories could range anywhere from about 1,750 to 2,800 depending on your age, sex, height, and how much you move throughout the day.
The Quick Estimate
The fastest way to ballpark your maintenance calories at 150 pounds is the “multiply by 15” rule. If you’re moderately active (exercising a few times a week and moving around during the day), 150 times 15 gives you 2,250 calories. This works as a starting point, but it’s a rough estimate that assumes average height, age, and body composition. For a more precise number, you need to account for the factors that make your metabolism different from someone else’s.
What Your Body Burns Calories On
Your daily calorie burn breaks down into three main categories, and understanding them helps explain why two people at the same weight can have very different maintenance needs.
The biggest share, 60% to 70% of your total burn, goes to keeping you alive. This is your basal metabolic rate: the energy your body uses for breathing, circulation, temperature regulation, and keeping every cell functioning. For a 150-pound person, this typically falls between 1,300 and 1,700 calories per day depending on sex, height, and age.
About 10% of your calories go toward digesting food. This is called the thermic effect of food, and it varies by what you eat. Protein costs the most to process, burning 15% to 30% of the calories it contains just through digestion. Carbohydrates use 5% to 10%, and fats use almost nothing at 0% to 3%. A higher-protein diet slightly raises your total daily burn, though the effect is modest.
The remaining 20% to 30% comes from physical activity, everything from formal exercise to walking around the grocery store, fidgeting, and standing at your desk. This is the category you have the most control over, and it’s the reason activity level changes your maintenance number so dramatically.
How Activity Level Changes the Number
Activity multipliers convert your resting calorie burn into a total daily number. The Food and Agriculture Organization of the United Nations classifies activity into three broad categories, each with a specific multiplier range applied to your basal metabolic rate:
- Sedentary or light activity (desk job, little exercise): multiplier of 1.4 to 1.69
- Moderately active (regular exercise or an active job): multiplier of 1.7 to 1.99
- Vigorously active (intense daily training or physical labor): multiplier of 2.0 to 2.4
For a 150-pound person with a basal rate around 1,500 calories, these multipliers produce a wide range. A sedentary person might maintain on about 2,100 calories, while someone training hard daily could need 3,000 or more. Multipliers above 2.4 are difficult to sustain over long periods. Most people overestimate their activity level. If you exercise three or four times a week but sit at a desk the rest of the day, you’re likely in the lower end of the moderately active range.
Sex, Height, and Age All Matter
The most widely validated formula for estimating your resting calorie burn is the Mifflin-St Jeor equation. For men, it runs higher than for women at the same weight, height, and age because of differences in body composition. To give a concrete sense of the gap: a 35-year-old man who is 5’10” and weighs 150 pounds has a resting metabolic rate around 1,590 calories. A 35-year-old woman who is 5’5″ and weighs 150 pounds comes in closer to 1,380 calories. That 200-calorie difference at rest translates to a similar gap in total daily maintenance.
Height matters because taller people have more tissue to maintain. Two people who both weigh 150 pounds but differ by four inches in height can have maintenance needs that differ by 100 to 150 calories per day.
Age is the factor people worry about most, but recent research suggests the picture is more nuanced than the old “metabolism slows after 30” claim. A large study highlighted by Harvard Health found that both total calorie expenditure and basal metabolic rate remain stable from age 20 through 60, regardless of sex. Weight gain during middle age appears to be driven more by changes in activity and eating patterns than by an inevitable metabolic slowdown. After 60, metabolism does gradually decline, but the effect during prime adult years is far smaller than most people assume.
Why Body Composition Creates Different Results
Two people can both weigh 150 pounds and have meaningfully different calorie needs based on how much of that weight is muscle versus fat. Muscle tissue burns roughly 4.5 to 7 calories per pound per day just at rest. Fat tissue burns far less. So a lean, muscular 150-pound person has a higher resting metabolism than someone at the same weight with more body fat. This is one reason standard formulas are estimates: they can’t see what’s happening beneath the scale.
Finding Your Actual Maintenance Number
Formulas give you a starting point. Finding your real maintenance calories requires a few weeks of observation. Johns Hopkins Medicine recommends a gradual approach: once you’re eating at a level where your weight is stable over the course of a week, you’ve found your maintenance range. If your weight is still dropping, try adding about 200 calories of nutrient-dense food per day for a week and reassess.
Weigh yourself at the same time each day, ideally in the morning, and look at weekly averages rather than daily fluctuations. Water retention from salt, carbohydrates, and hormonal shifts can swing the scale by two to four pounds in a single day, so any individual reading is unreliable. If your weekly average stays within about a pound over two to three weeks, you’ve dialed in your maintenance calories.
Track your food intake honestly during this period. Most people underestimate what they eat by 20% to 40%, often forgetting cooking oils, beverages, and small snacks. A food scale is more accurate than measuring cups for solid foods, but even consistent use of an app without a scale gets you closer than guessing.
Sample Ranges for a 150-Pound Adult
These estimates assume average heights (5’4″ to 5’5″ for women, 5’9″ to 5’10” for men) and an age range of 25 to 45. Your number will shift based on your specific stats and true activity level.
- Sedentary woman, 150 lbs: approximately 1,750 to 1,900 calories
- Moderately active woman, 150 lbs: approximately 2,000 to 2,200 calories
- Very active woman, 150 lbs: approximately 2,300 to 2,600 calories
- Sedentary man, 150 lbs: approximately 2,000 to 2,150 calories
- Moderately active man, 150 lbs: approximately 2,250 to 2,500 calories
- Very active man, 150 lbs: approximately 2,600 to 2,900 calories
These ranges overlap in places, which reflects reality. A muscular, active woman at 150 pounds can easily need more calories than a sedentary man at the same weight. Use the ranges as a neighborhood to start in, then let your scale and food log narrow it down over two to four weeks.