A 150-pound woman needs roughly 1,800 to 2,200 calories per day, depending on age and activity level. That range covers most adults, but your specific number shifts meaningfully based on how much you move, how old you are, and whether you’re trying to maintain, lose, or gain weight.
Your Baseline: Basal Metabolic Rate
Your body burns a significant number of calories just keeping you alive. Breathing, circulating blood, repairing cells, regulating temperature: all of this costs energy even if you stayed in bed all day. This baseline burn is called your basal metabolic rate, or BMR.
The most widely used formula for estimating BMR in women is: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. For a 150-pound woman who is 5’5″ and 35 years old, that works out to about 1,385 calories per day. A 25-year-old at the same height and weight would land around 1,435, while a 50-year-old would be closer to 1,310. Age chips away at your baseline by roughly 50 calories per decade after your twenties.
How Activity Level Changes the Number
BMR is just the starting point. Your actual daily calorie need, often called total daily energy expenditure, depends on how active you are. To estimate it, you multiply BMR by an activity factor:
- Sedentary (desk job, little exercise): BMR × 1.2
- Lightly active (light movement or 1–2 workouts per week): BMR × 1.375
- Moderately active (3–5 workouts per week): BMR × 1.55
- Very active (intense daily training or active sports): BMR × 1.725
Using our example of a 35-year-old, 5’5″, 150-pound woman with a BMR of about 1,385:
- Sedentary: ~1,660 calories/day
- Lightly active: ~1,905 calories/day
- Moderately active: ~2,145 calories/day
- Very active: ~2,390 calories/day
These numbers align with broader federal guidelines, which place adult women between 1,600 and 2,400 calories daily depending on activity. After age 60, the range narrows to roughly 1,600 for sedentary women and 2,000 for active ones.
Calorie Targets for Weight Loss
If your goal is to lose weight, the math is straightforward: one pound of body fat represents about 3,500 calories. Cutting 500 calories per day from your maintenance number creates a deficit that adds up to roughly one pound lost per week. You can split that deficit between eating less and moving more, which tends to feel more sustainable than diet restriction alone.
For our example woman maintaining at around 1,900 calories (lightly active), a 500-calorie daily deficit would mean eating about 1,400 calories per day. That’s still above the safety floor. Harvard Health and most weight management programs recommend that women not drop below 1,200 calories daily without medical supervision, because going lower makes it very difficult to get adequate vitamins, minerals, and energy for basic body functions.
A more moderate deficit of 250 calories per day produces slower results (about half a pound per week) but is easier to maintain long term and less likely to trigger the fatigue and irritability that come with aggressive calorie cuts.
Why Two 150-Pound Women Can Need Different Amounts
Weight alone doesn’t tell the full story. Body composition matters. Muscle tissue burns roughly 4.5 to 7 calories per pound per day at rest, while fat tissue burns considerably less. Muscle contributes about 20% of your total daily energy expenditure, compared to only about 5% from fat. So a 150-pound woman who strength trains regularly and carries more lean mass will have a higher resting metabolism than a 150-pound woman with a higher body fat percentage, even if their height and age are identical.
The practical difference isn’t enormous. Adding 4 to 5 pounds of muscle through a consistent resistance training program (which research suggests is a realistic gain over 8 to 12 months) increases resting calorie burn by about 50 calories per day. That’s modest on its own, but it compounds over time and comes with other metabolic benefits that support weight management.
How to Split Those Calories Across Macronutrients
Once you have a calorie target, the next question is what those calories should look like. The Dietary Guidelines for Americans recommend that adults get 10–35% of calories from protein, 20–35% from fat, and 45–65% from carbohydrates. For a woman eating 1,900 calories per day, that translates to roughly:
- Protein: 48–166 grams (the RDA minimum is 0.36 grams per pound, or about 54 grams for a 150-pound woman)
- Fat: 42–74 grams
- Carbohydrates: 214–309 grams
Those ranges are wide because individual needs vary. If you’re strength training or trying to preserve muscle while losing weight, eating toward the higher end of the protein range helps. If you’re mostly sedentary and focused on heart health, keeping fat in the middle of its range and prioritizing unsaturated sources makes more sense. The exact split matters less than consistently hitting your overall calorie target with mostly whole foods.
Breastfeeding and Other Calorie Adjustments
Certain life stages shift your calorie needs significantly. Breastfeeding is the biggest one: producing milk requires an additional 450 to 500 calories per day on top of your normal maintenance calories, according to the National Institutes of Health. For a lightly active 150-pound woman, that could push daily needs to roughly 2,350 to 2,400 calories. Women who are breastfeeding and also trying to gradually lose pregnancy weight should be cautious about cutting calories too aggressively, since milk production depends on adequate energy and nutrient intake.
Pregnancy itself increases calorie needs as well, though the amount varies by trimester. Chronic stress, poor sleep, and certain medications can also nudge your metabolism in either direction, making calculator estimates less precise. If your weight isn’t responding the way the math predicts after several consistent weeks, your actual energy needs may differ from the formula, and adjusting by 100 to 200 calories in either direction is a reasonable next step.