Calorie Deficit Calculator

A calorie deficit is when you take in fewer calories than you burn.  

Calories are energy from the food and drinks you consume that powers your body. When you eat more calories than you burn, your body stores the extra fuel (often as fat) for later use. But when you burn more calories than you take in, your body taps into its reserves to keep running. In other words, it’s forced to break down stored body fat for energy, leading to weight loss.

A calorie deficit can be achieved in two ways:

• Reducing your daily calorie intake 

• Increasing your physical activity 

How many calories you need — and, in turn, how big your calorie deficit should be to lose weight — depends on factors such as age, sex, weight, height, activity level, and metabolism. 

Plus, the quality of the calories you consume is also important. Sure, you can meet your deficit with processed foods, but they won’t fill you up, keep you energized, or support sustainable weight loss like nutrient-rich, whole foods.

To figure out your calorie deficit, you first need to know how many calories your body burns each day to maintain your current weight. This number is called your total daily energy expenditure (TDEE). It includes the energy your body uses for basic functions like breathing and digestion, plus anything you burn through movement and exercise.

Once you know your TDEE (which you can figure out using our TDEE calculator!), you can subtract the number of calories you eat in a day to figure out your calorie deficit.

For example, if your TDEE is 2,000 calories and you want to lose about one pound per week, you’ll likely have to maintain a 500-calorie deficit per day. So, you’ll aim to eat 1,500 calories per day. 

While these calculations don’t factor in temporary factors like water weight or constipation, they can be helpful for understanding and planning weight changes in the longer term.

Many people trying to lose weight aim for a daily deficit of about 300–700 calories, which tends to support healthy, sustainable weight loss over time. A deficit of 500–1,000 calories, in particular, has been shown to promote healthy weight loss of at least 1–2 pounds per month for many people. Creating too large a deficit can slow your metabolism and make it harder to maintain your results, so moderate changes are usually the most effective.

Also key to a safe and effective calorie deficit? The duration. Most people follow a reduced-calorie diet for a few months until they hit their target weight. How long you stay in a deficit depends on your personal goals. But what matters most is finding a pace that feels sustainable — one that helps you make steady progress while still feeling energized and well-fed. (More on that later.)

It’s also important to remember that while looking at numbers alone can help you with weight loss, it’s important to make sure you are getting good quality, nourishing calories to maintain your personal health. Not all calorie deficits are created equally, and an imbalanced diet could cause problems for your body.

An unhealthy calorie deficit happens when you consistently eat too little — more than just a small cut in calories — and for too long. While it might seem like a fast track to weight loss, going too hard with calorie restriction can backfire. Research shows that extreme calorie cuts can actually slow how many calories your body burns (aka your metabolism) and increase hunger signals, making it harder to keep losing weight — and to keep it off later on. 

Even more importantly, eating too little for too long can lead to nutrient deficiencies and symptoms such as:

• Dizziness 

• Fatigue 

• Muscle loss

• Excessive hunger

• Sleep disruptions

For these reasons and more, healthcare providers generally recommend creating a smaller calorie deficit and losing weight at a slower, steadier rate. This typically means eating at least 1,500 and 1,200 calories per day for males and females, respectively, though this number is likely to be even higher depending on factors like your height or activity level. (Another way to look at it is losing up to 2 pounds per week.)