Calorie calculator (TDEE)

What your result actually means

The main number this calculator gives you is your total daily energy expenditure, or TDEE. It's an estimate of how many calories you burn on an average day, all things included. If you ate about that many calories most days, your weight would tend to stay roughly the same over time. That's why it's often called your maintenance calories.

It helps to know where those calories go. Your daily energy use breaks down into four broad parts:

• Resting metabolism. Even lying still, your body uses energy to keep your heart beating, your lungs breathing, your brain working and your body temperature steady. For most people this is the biggest share, often more than half of the daily total.
• Digesting food. Breaking down and storing what you eat takes energy too, roughly a tenth of your daily intake. Protein takes a bit more energy to process than carbohydrate or fat.
• Planned exercise. Workouts, runs, classes and sports. This part varies a lot from person to person and day to day.
• Everyday movement. Walking to the car, climbing stairs, cooking, cleaning, fidgeting and standing. It sounds minor, but the difference between a very still day and a very busy one can add up to a few hundred calories.

How this calculator works

Your total daily energy expenditure (TDEE) has two main parts: the energy your body uses at rest, called basal metabolic rate (BMR), and everything you do on top of that, from walking around to working out.

1. Resting energy (BMR) uses the Mifflin-St Jeor equation, published in 1990 and widely used by dietitians:
   • Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
   • Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
2. Activity multiplies BMR by a factor from 1.2 (sedentary) to 1.9 (extra active).
3. Goals subtract or add a modest amount: 250–500 calories a day for gradual change.

Worked example

A 30-year-old woman, 165 cm tall and 65 kg, who trains three times a week:

• BMR = 10 × 65 + 6.25 × 165 − 5 × 30 − 161 = 650 + 1,031 − 150 − 161 = 1,370 calories
• TDEE = 1,370 × 1.375 (lightly active) ≈ 1,880 calories a day to maintain her weight
• A 250-calorie deficit gives about 1,630 calories a day for slow, steady loss

If you use US units, the calculator converts your height and weight to centimeters and kilograms before running the same formula, so the result is identical either way.

Choosing your activity level honestly

The activity factor has a bigger effect on your result than any other input. For most adults, moving up one level adds roughly 200 to 350 calories a day, so it's worth picking carefully. A few pointers:

• Think about a typical week, not your best week. If you plan to train four times but usually manage two, choose the level that matches two.
• Your job counts. A nurse, server or warehouse worker who is on their feet all day moves far more than someone at a desk, even before any workouts.
• Workout length and effort matter. A gentle 20-minute walk is not the same as an hour of hard training, even though both count as a session.
• When you're unsure between two levels, start with the lower one. It's easier to add food later than to figure out why your weight is creeping up.

The activity factor already includes your usual exercise. If you also add back the calories a fitness app says you burned in a workout, you count that exercise twice.

How to use your number over the first few weeks

Think of the result as a first guess that you'll fine-tune with real data. Here's a simple way to do that:

1. Pick a starting target. To maintain, use your TDEE. To lose weight gradually, subtract 250 to 500 calories. To gain, add a similar small amount.
2. Track for two to four weeks. Eat close to your target most days. Roughly right and consistent beats perfect for three days and then nothing.
3. Weigh in a few times a week. Same scale, same time of day, ideally in the morning before eating.
4. Compare weekly averages. Average each week's weigh-ins and compare one week to the next, not one morning to the next.
5. Adjust in small steps. If the trend isn't moving as expected after two weeks or more, change your intake by 100 to 200 calories and give it another two weeks.

Protein deserves a spot in that plan too. Getting enough helps you keep muscle while eating a little less, and it tends to keep you fuller between meals.

Why your weight jumps around from day to day

It's normal for scale weight to swing by 1 to 2 pounds (about 0.5 to 1 kg), and sometimes more, from one day to the next. That's mostly water and the contents of your digestive system, not fat. Common causes include:

• Salty meals. Your body holds on to extra water after a high-sodium day, and lets it go over the next day or two.
• Carbohydrates. Your muscles and liver store carbs along with water, so a carb-heavy day can nudge the scale up and a low-carb day can drop it quickly.
• Hard workouts. Muscles hold some extra fluid while they recover, especially after a new or tougher session.
• Hormonal cycles. Many women see temporary water retention at certain points in their menstrual cycle.

Weekly averages smooth out this noise and show the real trend, so you don't overreact to a single high reading.

What the number can't tell you

Formulas work on averages. Muscle mass, genetics, sleep, stress, medications and hormonal conditions can all move your real number up or down. That's why the weekly check-in described above matters more than the starting number. After a few weeks of eating close to your target:

• Weight steady? You found your maintenance.
• Drifting up or down? Adjust by 100–200 calories and check again in two weeks.

When this estimate may not fit you

The Mifflin-St Jeor equation was built from data on healthy adults. It's less reliable, or simply not the right tool, in some situations:

• Pregnancy and breastfeeding. Energy needs change through pregnancy and while nursing. Don't plan a calorie deficit during this time without guidance from your doctor or midwife.
• Teens. Young people are still growing and need enough energy for that. Teens shouldn't cut calories to lose weight unless a doctor recommends it.
• Very muscular people. The formula doesn't know how much of your weight is muscle, so it can underestimate needs for people who carry a lot of it.
• Older adults. Needs vary widely with health, medications and activity, and keeping muscle becomes a higher priority. Large deficits are rarely a good idea.
• Medical conditions and medications. Thyroid conditions, diabetes, heart or kidney disease and some medications can all change your needs or make diet changes riskier.
• A history of disordered eating. Counting calories can be unhelpful or harmful. Please talk to a health professional before using any calorie target.

If any of these apply to you, or you're thinking about eating much less than this calculator suggests, a doctor or registered dietitian can give you advice that fits your situation far better than a formula can.

Where to go from here

Regular activity helps you keep muscle and makes maintaining your weight easier. See how much exercise you need each week, or start with a beginner strength training plan. Short nights tend to raise appetite, so sleep and recovery matter too.

For a step-by-step version, read how to calculate your maintenance calories. To decide how much of those calories should come from protein, use the protein calculator.

Based on: Mifflin-St Jeor equation (1990).