Precision Nutrition’s
Weight Loss Calculator
Calorie deficit? Macros? Here's what it really takes to reach your goals.


Want to know how many calories you should eat to lose weight? We’ve made it easy. Just click the “Get Started” button below and enter your information.

(Plus, once we calculate your calorie and macronutrient needs, we’ll send you a free, personalized nutrition plan for achieving the results you want.)

An illustration of the Precision Nutrition Weight Loss Calculator for understanding how to get into a calorie deficit and find the right portions surrounded by fruits, grains, fish, and vegetables.

Weight Loss Calculator
How much should you eat? Let’s find out.

Why This Weight Loss Calculator Is Special

One of the most common questions Precision Nutrition certified nutrition coaches get from their new clients:

“I’ve been tracking my calories in and calories out religiously… but I’m not losing as much weight as I should. Why isn’t this working?!?”

Yes, conventional wisdom states that reducing your calorie intake (or increasing the amount you burn) by 500 calories a day should lead to about 1 pound of fat loss per week. (Math: 500 calories a day x 7 days = 3500 calories a week = 1 pound.)

But that conventional wisdom is wrong. As discussed in this article all about the myth of metabolic damage, your metabolism is adaptive. As you eat less, your metabolism slows, throwing off common assumptions about calorie balance.

This excellent weight loss calculator—based on the NIH Body Weight Planner and adapted from research collected at the National Institute of Diabetes and Digestive and Kidney Diseases—takes into account the adaptive nature of metabolism and gives more accurate information on how hard you’ll have to work (and how long it may take) to reach your goals.

Advantages of this Weight Loss Calculator

To understand why this calculator is so helpful, let’s use an example client: Vanessa.

She’s 40 years old, 5’ 6” tall, weighs 185 pounds, has a very low level of activity at work, and a moderate level of exercise activity.

Based on this information, the calculator has determined that she needs around 2,445 calories per day to maintain her weight.

Let’s say Vanessa would like to lose 40 pounds (so a goal weight of 145 pounds) in a sustainable way over the course of the next year, without doing any additional exercise.

The calculator suggests she’ll need to reduce her food intake to around 1,770 calories per day. (That’s 675 calories fewer than required for maintenance.)

If you do conventional calorie math, these numbers don’t make sense.

A daily calorie deficit of 675 calories would lead to a deficit of 246,375 calories over a full year. (Math: 675 calorie deficit x 365 days = 246,375 calories.)

This would, theoretically, lead to a 70-pound weight loss for Vanessa. (Math: 246,375 calorie deficit / 3,500 calories in 1 pound of weight = 70 pounds lost.)

But the body doesn’t work that way. Instead, Vanessa would lose only about 40 pounds. (Which is still awesome, obviously.)

Why this very large disparity?

As mentioned above, your metabolism adjusts as you eat less and lose weight. And conventional math doesn’t take this complex nature of human metabolism into account.

That’s why it’s important to make sure your expectations about weight loss and body change are in line with how your body actually works.

This calculator helps with that. It makes it easier to set appropriate behavior goals and gives you a more realistic view of what your potential progress could look like.

More Benefits of this Weight Loss Calculator

The Precision Nutrition Weight Loss Calculator is special for other reasons, too.

It not only takes into account your personal details (height, weight, age, sex), physical activity levels, and the amount of weight you want to lose, but also allows you to:

  • Choose your dietary preference. (You can select from Paleo, keto, vegetarian, fully plant-based/vegan, Mediterranean, and of course, “anything”)
  • Adjust your macronutrient preference. (If desired, you can change the amount of carbs, fat, or protein to better fit your needs.)
  • Use “hand portions” to easily track your food intake. (More on this below.)

The Weight Loss Calculator takes all this information and uses it to estimate your calorie and macronutrient needs. It also automatically converts those numbers into food portions that are equivalent to parts of your hands. (For example: your palm, fist, thumb, and cupped hand.)

The benefit: You don’t ever need to weigh and measure your food, or log the details of every meal into a food tracking app.

Instead, you can use our hand portion tracking system to take the hassle out of calorie and macro tracking—and still achieve your targets.

Once the Weight Loss Calculator runs your numbers, it’ll generate a FREE nutrition plan that’s personalized for your body, preferences, and goals and will show you exactly what to do.

Ready to get started? Enter your information in the Weight Loss Calculator above, and we’ll take care of the rest.

If you’re a coach, or you want to be…

You can help people build nutrition and lifestyle habits that improve their physical and mental health, bolster their immunity, help them better manage stress, and get sustainable results. We'll show you how.

If you’d like to learn more, consider the PN Level 1 Nutrition Coaching Certification.

Be first in line—and start leveling up your nutrition coaching skills today!

Spots in the #1 rated PN Level 1 Nutrition Coaching Certification open on September 21st. Get on the free presale list today and you'll...

  • Get instant access to our 35-page eBook, "Your Best Nutrition Starts Here".
  • Receive free tips on coaching, marketing your services, and attracting clients—plus get a sneak peek inside the PN Nutrition Certification.
  • Enroll 24 hours earlier than everyone else—to increase your chances of getting a spot.
  • Save up to 30% off the general public price when you enroll.