To lose weight, you need to consume fewer calories than your body burns. But how many calories is that? The number is different for everyone. It depends on your unique body and how active you are. Let's figure out your personal calorie target.

Your body is always working, even when you're resting. It's busy pumping blood, breathing, and keeping your temperature stable. The energy required for these basic, life-sustaining functions is called your Basal Metabolic Rate, or BMR.

Think of your BMR as the number of calories you'd burn if you stayed in bed all day. We can estimate it with a formula called the Mifflin-St Jeor equation, which is one of the most accurate methods available.

For example, let's calculate the BMR for a 35-year-old woman who is 165 cm tall and weighs 70 kg.

Her BMR would be: $(10 \times 70) + (6.25 \times 165) - (5 \times 35) - 161 = 700 + 1031.25 - 175 - 161 = 1395.25$. So, her body burns about 1,395 calories per day just to stay alive.

Of course, most of us don't lie in bed all day. We move around, work, and exercise. To get a full picture of your daily calorie needs, we need to adjust your BMR for your activity level. This gives us your Total Daily Energy Expenditure (TDEE).

To find your TDEE, you multiply your BMR by an activity factor that matches your lifestyle. Find your activity level in the table below.

Using our previous example, if the 35-year-old woman is moderately active, we'd calculate her TDEE like this:

$1395.25$ (BMR) $\times 1.55$ (Activity Multiplier) $= 2162.6$

Her body burns approximately 2,163 calories on an average day. This is her maintenance number, the amount she'd eat to keep her weight the same.

Weight loss happens when you consistently consume fewer calories than your TDEE. This is called a calorie deficit.

To lose about 1 pound (0.45 kg) per week, you need a deficit of roughly 3,500 calories over the course of that week. This breaks down to a 500-calorie deficit per day.

So, for our example woman with a TDEE of 2,163 calories, a good weight loss target would be:

$2163 - 500 = 1663$ calories per day.

Eating around 1,660 calories per day would put her on track to lose about one pound per week without feeling overly restricted.

Ready to test your knowledge? Take this quick quiz to see if you've got the basics down.

Now you have the tools to estimate your own calorie needs. Remember, these calculations are a starting point. Your metabolism is unique, so you may need to adjust your intake based on your results.