Use this calorie deficit calculator to easily figure out how many calories you need per day to lose weight.
Ready to make a lasting change?
A healthier you, wherever you are.
What is a calorie deficit?
To lose weight, you must take in fewer calories than your body burns—what’s called a calorie deficit.
Eating in a deficit of 500 calories per day will typically result in about one pound lost per week—research shows that this is a healthy calorie deficit to allow your body to function at its best while also losing weight.
While you burn calories with exercise, your body is also constantly using energy (calories) to perform basic bodily functions like breathing, blood pumping, and using your brain.
How this calorie deficit calculator works
To find out how many calories you need to eat a day to lose weight, use this calorie deficit calculator. It uses your age, height, current weight, sex, and basic activity level to calculate the approximate number of calories your body uses in a day (your total daily energy expenditure or TDEE), based on the Harris-Benedict equation.
It subtracts how many calories you need to burn to lose weight from your TDEE—while also eating a healthy number of calories to keep your body functioning at its best—to create the Weight Loss Zone, which is a range of a few hundred calories.
Eating closer to the lower end of the Weight Loss Zone typically leads to greater weight loss (about 2 pounds or 1 kilogram lost per week), while eating at the higher end of the Weight Loss Zone typically leads to a more moderate weight loss (about 0.5 pound or 0.25 kilograms lost per week.)
It’s important to note that you should be eating within the Weight Loss Zone—not below it. Your body needs calories to function properly. Going below your zone can lead to headache, fatigue, a weakened immune system, and slow your metabolism down. Plus, it isn’t sustainable in the long term.
If you’re new to tracking your calories, starting at the higher end of the Weight Loss Zone might feel like a more flexible and realistic place to start. If you plan to log your meals and track calories consistently, you should gain more confidence in staying within your range.
While based in science and research, this calorie deficit calculator is more of an approximation and doesn’t account for other lifestyle factors that might impact your calorie needs.
For example, if you have an increased activity level or are lactating, it is recommended that you take in more calories. Please consult with your doctor before embarking on a weight-loss plan, especially if you’re lactating—calorie needs vary based on lactation intensity.
How Noom can help you lose weight with a calorie deficit
Noom Weight can help you lose weight by recommending a calorie range for you to eat within, which also accounts for daily activity—you can use your phone as a pedometer to track steps or connect a smart device like a Fitbit or Apple Watch.
Noom Weight will also help keep you on track with a structured system that combines psychology-based lessons, a color-coded food system, and other tools needed for long-term weight loss.