How Many Calories Should I Eat Per Day? The Complete Guide
"How many calories should I eat?" is the single most searched nutrition question on the internet. The answer depends on your age, gender, height, weight, activity level, and goal — but you don't need a degree in nutrition to figure it out.
This guide walks you through the exact calculation in three steps. By the end, you'll have your personalized daily calorie target for weight loss, maintenance, or muscle building.
The Short Answer
Most adults need 1,600–3,000 calories per day to maintain their current weight. The exact number depends on your age, gender, height, weight, and how active you are.
Here are the general ranges from the USDA Dietary Guidelines for Americans 2020–2025:
| Gender | Sedentary | Moderately Active | Active |
|---|---|---|---|
| Women (19–50) | 1,600–1,800 kcal | 1,800–2,200 kcal | 2,000–2,400 kcal |
| Men (19–50) | 2,000–2,400 kcal | 2,200–2,800 kcal | 2,400–3,200 kcal |
But these are population averages. A 55 kg sedentary woman and a 90 kg active man have vastly different needs. To find your number, you need to calculate it in three steps: BMR → TDEE → Goal Adjustment.
Step 1: Calculate Your BMR (Basal Metabolic Rate)
Your BMR is the number of calories your body burns at complete rest — just keeping your organs running, maintaining body temperature, and breathing. For most people, BMR accounts for 60–75% of total daily calorie burn.
The most widely validated formula is Mifflin-St Jeor (Mifflin et al., 1990). It uses four variables: weight, height, age, and gender:
Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161
Example: A 30-year-old woman, 65 kg, 165 cm:
BMR = (10 × 65) + (6.25 × 165) − (5 × 30) − 161
BMR = 650 + 1,031 − 150 − 161 = 1,370 kcal
This means her body burns about 1,370 kcal per day just by existing — before any movement or exercise.
What about Katch-McArdle?
If you know your body fat percentage, the Katch-McArdle formula is more accurate. It uses lean body mass instead of total weight: BMR = 370 + (21.6 × lean_mass_kg). This is especially useful for muscular individuals or those with higher body fat. Read more about how TDEE formulas work.
Use our free TDEE Calculator → to get your BMR and TDEE instantly without manual math.
Step 2: Multiply by Activity Level (= Your TDEE)
BMR is only your resting calorie burn. To get your TDEE (Total Daily Energy Expenditure) — the total calories you burn including movement — multiply your BMR by an activity factor:
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise |
| Lightly active | 1.375 | Light exercise 1–3 days/week |
| Moderately active | 1.55 | Moderate exercise 3–5 days/week |
| Very active | 1.725 | Hard exercise 6–7 days/week |
| Extremely active | 1.9 | Physical job + hard exercise daily |
Example continued: Our 30-year-old woman exercises moderately (3–4 times per week):
TDEE = 1,370 × 1.55 = 2,124 kcal
This is her maintenance calories — the amount she needs to eat to stay at her current weight of 65 kg.
Apple Watch users get better accuracy
Activity multipliers are estimates. They assume a "moderately active" person burns roughly the same calories every day — but real activity varies. If you wear an Apple Watch, apps like AI Food Coach can use your real measured basal and active calories from HealthKit instead of relying on a multiplier. This makes your TDEE accurate to the day, not just an average.
Step 3: Adjust for Your Goal
Your TDEE tells you how many calories you burn. What you eat relative to that number determines whether you lose, maintain, or gain weight.
Weight Loss (Calorie Deficit)
To lose weight, eat fewer calories than your TDEE. The size of the deficit determines how fast you lose:
One kilogram of body fat stores approximately 7,700 kcal of energy. So:
- 250 kcal/day deficit → ~0.25 kg lost per week (gentle, sustainable)
- 500 kcal/day deficit → ~0.5 kg lost per week (recommended for most people)
- 750 kcal/day deficit → ~0.75 kg lost per week (aggressive)
- 1,100 kcal/day deficit → ~1 kg lost per week (maximum safe rate)
Example continued: Our woman wants to lose 0.5 kg per week:
Target = 2,124 − 500 = 1,624 kcal per day
Important safety minimums: calorie targets should not drop below 1,200 kcal for women or 1,500 kcal for men without medical supervision. Below these thresholds, it becomes very difficult to get adequate micronutrients.
Your weight loss target: TDEE minus 500 kcal is the sweet spot for most people — fast enough to see results, slow enough to maintain muscle mass and energy levels. Use our TDEE Calculator to find your number.
Weight Maintenance
Eat at your TDEE. This sounds simple, but it is the hardest goal in practice because it requires you to know your actual TDEE — not an estimate from a formula you ran once.
Your TDEE changes as your weight, activity, and body composition change. A person who loses 10 kg has a lower TDEE than before. This is why many people regain weight after a diet — they go back to eating the same amount as before, but their body now burns less.
The solution is to track your weight alongside your calories. If your weight stays stable over 2–4 weeks, you have found your true maintenance calories. If it drifts up, you are eating slightly above TDEE. If it drifts down, you are slightly below.
Muscle Building (Calorie Surplus)
To build muscle, eat more than your TDEE. The body needs extra energy to synthesize new muscle tissue. A surplus of 250–500 kcal per day is sufficient for most people — larger surpluses mostly add fat, not extra muscle.
Protein becomes especially important here. Research suggests 1.6–2.2 g of protein per kg of body weight for optimal muscle protein synthesis. For an 80 kg man, that is 128–176 g of protein per day.
Good high-protein sources include chicken breast (31 g protein per 100 g, only 165 kcal) and eggs (13 g protein per 100 g, 155 kcal).
How Many Calories Should a Woman Eat?
The following table shows estimated daily calorie needs for women at three activity levels, based on the USDA Dietary Guidelines for Americans 2020–2025. These are maintenance calories — for weight loss, subtract 300–500 kcal.
| Age | Sedentary | Moderately Active | Active |
|---|---|---|---|
| 19–25 | 2,000 kcal | 2,200 kcal | 2,400 kcal |
| 26–30 | 1,800 kcal | 2,000 kcal | 2,400 kcal |
| 31–50 | 1,800 kcal | 2,000 kcal | 2,200 kcal |
| 51–60 | 1,600 kcal | 1,800 kcal | 2,200 kcal |
| 61+ | 1,600 kcal | 1,800 kcal | 2,000 kcal |
These numbers assume average height and weight for each age group. Your individual needs may be higher or lower depending on your body size and composition. A tall, muscular woman will need more than a petite woman of the same age — which is why calculating your personal BMR and TDEE gives a much better answer than any table.
You can also check your BMI as a starting reference point, but keep in mind that BMI does not account for muscle mass or body composition.
How Many Calories Should a Man Eat?
The same USDA guidelines provide calorie estimates for men:
| Age | Sedentary | Moderately Active | Active |
|---|---|---|---|
| 19–25 | 2,400 kcal | 2,800 kcal | 3,000 kcal |
| 26–35 | 2,400 kcal | 2,600 kcal | 3,000 kcal |
| 36–50 | 2,200 kcal | 2,600 kcal | 2,800 kcal |
| 51–60 | 2,200 kcal | 2,400 kcal | 2,800 kcal |
| 61+ | 2,000 kcal | 2,200 kcal | 2,600 kcal |
Men generally need more calories than women due to higher average muscle mass and body weight. However, the gap shrinks with age as muscle mass naturally decreases. The most common mistake men make is overestimating their activity level — a desk job with three gym sessions per week is "lightly active" or at most "moderately active," not "very active."
How to Track Your Calories (Without Going Crazy)
Knowing your calorie target is only useful if you can track what you eat. The good news: modern tools make this much easier than manually looking up every food in a database.
1. Photo AI Recognition
Take a photo of your meal and let AI estimate the calories and macros. This is the fastest method — it takes about 5 seconds. For better accuracy, place your food on a kitchen scale so the AI can read the exact weight from the display.
2. Manual Entry and Search
Search for foods by name or enter nutrition values manually. For common foods, the calorie count is well established — for example, cooked white rice is about 130 kcal per 100 g, and a medium egg is about 72 kcal.
3. Barcode Scanning
Scan the barcode on packaged foods to pull up exact nutrition data from the product database. This is the most accurate method for anything with a label — you get the exact manufacturer values.
The best tracking method is the one you will actually use. Photo AI is the fastest and easiest to maintain as a daily habit. Barcode scanning is the most precise for packaged foods. Manual entry gives you full control. Most people use a combination of all three.
AI Food Coach combines all three methods in one app — snap a photo, scan a barcode, or type in your food. It calculates your TDEE from real data and updates your calorie target dynamically as you eat.
Common Mistakes When Counting Calories
1. Eating Too Few Calories
Cutting calories aggressively seems like it should speed up results, but it often backfires. Very low calorie diets (below 1,200 kcal for women or 1,500 kcal for men) can cause muscle loss, fatigue, nutrient deficiencies, and metabolic slowdown. Your body adapts to the restriction by lowering its metabolic rate — and when you eventually eat normally again, you regain weight faster because your metabolism is suppressed.
A moderate deficit of 300–500 kcal below TDEE is more effective long-term than a crash diet.
2. Not Counting Liquid Calories
Juice, soda, alcohol, milk in coffee, smoothies — these add up quickly. A large latte can be 250 kcal. A glass of orange juice is about 110 kcal. Two glasses of wine add 300 kcal. People who "eat healthy but can't lose weight" are often consuming 300–500 untracked liquid calories per day.
3. Ignoring the Thermic Effect of Food (TEF)
Your body burns calories digesting food. Protein has the highest thermic effect — about 25% of its calories are used for digestion. Carbohydrates cost about 7.5%, and fat costs about 2.5%. On a high-protein diet, TEF can add 100–200 extra calories burned per day — which most calorie trackers ignore entirely.
This is one reason high-protein diets are effective for weight loss beyond just satiety: they increase total calorie burn. Try our TEF Calculator to see how much your diet composition affects your daily burn.
See our full methodology and scientific sources →
Frequently Asked Questions
Calculate Your Exact Calorie Target
AI Food Coach calculates your TDEE from real data — BMR, activity from Apple Watch, and TEF from every meal you log. No guessing, no static numbers. Your calorie target updates dynamically as you eat, move, and lose weight.
