How Many Calories Should I Eat Per Day? TDEE Explained

"How many calories should I eat?" is one of the most common health questions people ask, and for good reason. Whether you want to lose weight, gain muscle, or simply maintain your current physique, understanding your daily calorie needs is the foundation of any nutrition plan. The problem is that the answer is different for everyone.

Your ideal calorie intake depends on your age, sex, height, weight, and how active you are on a daily basis. Fortunately, there are well-established formulas that give you a solid starting point. Let's break down exactly how to calculate your number.

Understanding Your Basal Metabolic Rate (BMR)

Your Basal Metabolic Rate (BMR) is the number of calories your body burns just to keep you alive. We're talking about the energy needed for breathing, circulating blood, regulating body temperature, and keeping your organs functioning. Even if you stayed in bed all day and didn't move a muscle, your body would still burn this many calories.

For most people, BMR accounts for roughly 60-75% of total daily calorie expenditure. That's a huge chunk. It means the majority of the calories you burn each day have nothing to do with exercise. They're just the cost of being alive.

The Mifflin-St Jeor Equation

Several formulas exist for calculating BMR, but the Mifflin-St Jeor equation is widely considered the most accurate for most people. It was developed in 1990 and has been validated in numerous studies since then. Here's how it works:

For men:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161 + 166

For women:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Notice that the only difference between the two formulas is the constant at the end. Men generally have a higher BMR because they tend to carry more lean muscle mass, which is metabolically more active than fat tissue.

If you don't want to do the math by hand, our calorie calculator does all of this for you instantly. Just plug in your stats and get your number.

Activity Multipliers: From Couch to Athlete

BMR only tells you what your body burns at rest. To find your Total Daily Energy Expenditure (TDEE), the actual number of calories you need each day, you multiply your BMR by an activity factor. This accounts for everything from walking to the fridge to running a marathon.

Here are the standard activity multipliers:

• Sedentary (1.2): Desk job, little to no exercise. You drive to work, sit at a computer, drive home, and watch TV.
• Lightly Active (1.375): Light exercise or sports 1-3 days per week. Maybe a few walks or a casual gym session.
• Moderately Active (1.55): Moderate exercise 3-5 days per week. You hit the gym regularly or have a somewhat physical job.
• Very Active (1.725): Hard exercise 6-7 days per week. You're training with purpose and intensity most days.
• Extra Active (1.9): Very hard daily exercise plus a physical job, or training twice per day. Think professional athletes or construction workers who also work out.

Most people overestimate their activity level. Be honest with yourself here. If you work out three times a week but sit at a desk the other 12+ hours a day, "Lightly Active" is probably more accurate than "Moderately Active."

A Real-World Example

Let's walk through a complete calculation. Meet Jake: a 30-year-old male who weighs 180 lbs (82 kg), stands 5'10" (178 cm) tall, and is moderately active (works out 4 times a week).

Step 1: Calculate BMR

Using the Mifflin-St Jeor equation for men:
BMR = 10 × 82 + 6.25 × 178 − 5 × 30 − 161 + 166
BMR = 820 + 1,112.5 − 150 − 161 + 166
BMR = 1,787.5 calories/day

So even if Jake literally did nothing all day, his body would burn about 1,788 calories just to function.

Step 2: Apply Activity Multiplier

Jake is moderately active, so we multiply by 1.55:
TDEE = 1,787.5 × 1.55
TDEE = 2,771 calories/day

That's Jake's maintenance level: the number of calories he needs to eat each day to stay at exactly 180 lbs. If he eats more, he gains weight. If he eats less, he loses weight. Simple as that (in theory, at least).

Calories for Weight Loss

If your goal is to lose weight, you need to create a calorie deficit. The most commonly recommended approach is to subtract 500 calories per day from your TDEE. Since one pound of body fat contains roughly 3,500 calories, a 500-calorie daily deficit works out to about 1 pound of weight loss per week.

Using Jake's numbers:
Weight loss TDEE = 2,771 − 500 = 2,271 calories/day

That's still a very reasonable amount of food. Jake wouldn't need to starve himself. He'd just need to be a bit more mindful about portion sizes and food choices. At this rate, he could expect to lose about 4 pounds per month.

For a more aggressive approach, some people go with a 750 or even 1,000-calorie deficit. But larger deficits are harder to sustain and come with a higher risk of muscle loss, nutrient deficiencies, and metabolic slowdown. A moderate deficit of 500 calories is the sweet spot for most people.

Calories for Weight Gain

If you're trying to build muscle or simply gain weight, you need a calorie surplus. The recommended range is to add 250 to 500 calories per day above your TDEE.

For Jake:
Lean bulk = 2,771 + 250 = 3,021 calories/day
Standard bulk = 2,771 + 500 = 3,271 calories/day

A smaller surplus of 250 calories (often called a "lean bulk") minimizes fat gain while still providing enough fuel for muscle growth. A larger surplus of 500 calories will lead to faster weight gain, but more of that gain will be fat. Most experts recommend starting with the smaller surplus and adjusting based on results.

To figure out how to split those calories across protein, carbs, and fat, check out our macro calculator.

How Low Is Too Low?

There is a floor you shouldn't go below. Most nutrition experts and medical organizations recommend that women should not eat fewer than 1,200 calories per day and men should not eat fewer than 1,500 calories per day without medical supervision.

Going below these thresholds can lead to serious problems. Your body may not get enough essential vitamins and minerals. Your metabolism can slow dramatically as your body enters a conservation mode. You may lose significant muscle mass, which ironically makes it harder to keep weight off in the long run.

Very low-calorie diets (VLCDs) of 800 calories or less do exist, but they should only be followed under direct medical supervision. They're typically reserved for people with a BMI over 30 who haven't responded to other approaches.

Beyond Just Calories

While your total calorie intake matters most for weight management, it's not the whole picture. Where those calories come from matters too. 2,000 calories of chicken, vegetables, and whole grains will leave you feeling full, energized, and well-nourished. 2,000 calories of soda and candy will leave you hungry, sluggish, and nutritionally depleted.

A few practical tips to keep in mind:

• Protein is the most satiating macronutrient. Aim for 0.7-1g per pound of body weight if you're active.
• Fiber-rich foods like vegetables, fruits, and whole grains help you feel full on fewer calories.
• Track for at least two weeks to get a baseline. Most people are surprised by how much (or how little) they actually eat.
• Adjust based on results. If you're not losing weight at your calculated deficit, drop another 100-200 calories. Bodies don't always match the math perfectly.

Remember, any calorie calculator — including the formulas above — gives you an estimated starting point. Your actual needs may be slightly higher or lower depending on genetics, hormones, sleep quality, stress levels, and dozens of other factors. Use the number as a starting point, track your progress for 2-3 weeks, and adjust from there.

Ready to find your number? Use our calorie calculator to get your personalized daily calorie target in seconds.