A woman who is 5’7″ typically needs between 1,800 and 2,400 calories per day, depending on age, activity level, and weight goals. That’s a wide range because a 25-year-old who exercises regularly and a 55-year-old with a desk job have very different energy demands. Here’s how to find your number within that range.
Your Starting Point: The USDA Estimates
The Dietary Guidelines for Americans provide calorie estimates for women based on age and activity level. These assume a reference body weight, so they’re a useful baseline even though they don’t account for your specific weight. For women aged 19 to 50, the numbers look like this:
- Sedentary (desk job, no planned exercise): 1,800 to 2,000 calories
- Moderately active (walking 1.5 to 3 miles daily on top of normal activity): 2,000 to 2,200 calories
- Active (walking more than 3 miles daily or equivalent exercise): 2,200 to 2,400 calories
The higher end of each range applies to younger women (19 to 25), and the lower end applies as you move through your 30s and 40s. After age 50, needs drop further. A sedentary woman over 51 needs roughly 1,600 calories, while an active woman over 51 still needs around 2,200.
How to Calculate a More Personalized Number
The USDA ranges are helpful, but they don’t factor in your actual weight. For a more tailored estimate, you can calculate your basal metabolic rate, which is the number of calories your body burns just to stay alive (breathing, circulating blood, maintaining body temperature). The most widely used formula for women is:
(10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
For a 5’7″ woman (170.18 cm), here’s what that looks like at a few different weights and ages:
- Age 30, 140 lbs (63.5 kg): BMR of about 1,384 calories
- Age 30, 160 lbs (72.6 kg): BMR of about 1,475 calories
- Age 45, 140 lbs (63.5 kg): BMR of about 1,309 calories
- Age 45, 160 lbs (72.6 kg): BMR of about 1,400 calories
Your BMR is never the number you should eat. It’s just your body’s baseline. To get your actual daily calorie need, you multiply it by an activity factor:
- Sedentary (little or no exercise): BMR × 1.2
- Lightly active (exercise 1 to 3 days per week): BMR × 1.375
- Moderately active (exercise 3 to 5 days per week): BMR × 1.55
- Very active (hard exercise 6 to 7 days per week): BMR × 1.725
So a 30-year-old, 140-pound woman at 5’7″ who exercises moderately would need roughly 1,384 × 1.55, or about 2,145 calories per day to maintain her current weight. That same woman living a sedentary lifestyle would need closer to 1,661 calories.
Why Age Changes the Equation
Calorie needs peak around age 20 and then gradually decline. This happens for two reasons: your metabolism naturally slows, and most people lose small amounts of muscle mass each decade. Muscle tissue burns roughly 4.5 to 7 calories per pound per day just at rest, while fat tissue burns almost nothing. So as muscle decreases, your body’s resting energy needs drop with it.
The practical effect is significant. A sedentary woman between 19 and 25 needs about 2,000 calories daily. By 51, that same activity level calls for only 1,600 calories. That’s a 400-calorie difference, which is the equivalent of a full meal or snack disappearing from your daily budget. Staying physically active and maintaining muscle through strength training are the most effective ways to slow this decline.
Adjusting for Weight Loss
If your goal is weight loss rather than maintenance, the standard approach is to subtract about 500 calories from your daily maintenance number. This creates a deficit that leads to roughly one pound of weight loss per week. A 5’7″ woman whose maintenance need is 2,000 calories would aim for about 1,500 calories daily.
There is an important floor to keep in mind. Eating fewer than 1,200 calories per day puts you at risk for nutrient deficiencies and can actually work against you by slowing your metabolism. If your calculated deficit drops below 1,200, a smaller deficit with added exercise is a safer path to the same result.
Keep in mind that these calculations give you an estimate, not a prescription. Your body’s actual response depends on factors no formula captures, including genetics, sleep quality, stress levels, and hormonal fluctuations. Use the number as a starting point, then adjust based on how your weight, energy, and hunger respond over two to three weeks.
How to Split Those Calories
Once you know your calorie target, the balance of protein, fat, and carbohydrates matters for energy and satiety. The recommended ranges for adults are 10% to 35% of calories from protein, 20% to 35% from fat, and 45% to 65% from carbohydrates.
For a 5’7″ woman eating 2,000 calories, that translates to roughly 50 to 175 grams of protein, 44 to 78 grams of fat, and 225 to 325 grams of carbohydrates per day. If you’re physically active or trying to lose weight while preserving muscle, aiming for the higher end of the protein range (closer to 25% to 30% of total calories) can help you feel fuller and maintain lean mass. Protein-rich meals also require more energy to digest than carbohydrate- or fat-heavy ones, giving you a small metabolic advantage.
Quick Reference by Age and Activity
Here’s a simplified lookup for a 5’7″ woman at a healthy weight, based on the federal dietary guidelines:
- Ages 19 to 25, sedentary: 2,000 calories
- Ages 19 to 25, moderately active: 2,200 calories
- Ages 19 to 25, active: 2,400 calories
- Ages 26 to 50, sedentary: 1,800 calories
- Ages 26 to 50, moderately active: 2,000 calories
- Ages 26 to 50, active: 2,200 calories
- Ages 51 and older, sedentary: 1,600 calories
- Ages 51 and older, moderately active: 1,800 calories
- Ages 51 and older, active: 2,200 calories
These are maintenance estimates. Subtract up to 500 for gradual weight loss, or add 250 to 500 if you’re looking to build muscle through strength training. Your actual sweet spot will become clear after a few weeks of tracking how your body responds.