As you start to eat less on your weight loss journey, your metabolic rate adjusts. Conventional calorie math doesn’t take into account this complex nature of human metabolism.

Our calorie deficit calculator helps mitigate that by accounting for those metabolic changes. It makes it easier to set accurate expectations about weight loss and body fat change as well as behavior goals that provide a realistic view of your potential progress.

Our weight loss calculator takes numerous factors into account to get a complete look at your life and provide a personalized nutrition plan. This includes:

The weight loss calculator takes all this information and uses it to estimate your calorie and macronutrient needs so you can lose weight.

Our weight loss calculator automatically converts your calorie needs into food portions that are equivalent to different parts of your hand. This allows you to easily know how much to eat to lose weight—but without needing to weigh and measure your food, or log the details of every meal into a food tracking app.

Our hand portion tracking system takes the hassle out of calorie and macro tracking, but you can still achieve your targets.

The weight loss calculator is built with a number of different options so you can select what most closely aligns with your current lifestyle as well as your weight loss goals. We include several categories for dietary preferences and your physical activity levels, so the nutrition plan it generates is as personalized to your body, preferences, and goals as is possible to estimate.

This calculator uses the same baseline algorithm as the Precision Nutrition Macro Calculator to weight loss calorie needs. It factors in the adaptive nature of your metabolism to predict how long it’ll take you to reach your bodyweight goal.

This algorithm is a mathematically validated model based on the NIH Body Weight Planner and adapted from research collected at the National Institute of Diabetes and Digestive and Kidney Diseases.

The macronutrients are calculated by many rules:

1. Protein is set on a grams per pound of bodyweight basis, at a range of 0.65-1.35 g/lb, depending upon sex, weight, goal, and activity level. (For very low-fat and very low-carb options, protein is set at 20% of calories, not on a bodyweight basis.)

2. Protein needs are also set on a sliding scale since, on average, even within the same goal and activity level, heavier folks would generally have a greater body fat percentage than lighter folks. Therefore, they require a smaller amount of protein on a grams per pound basis (though still higher on an absolute basis).

3. Then, dependent upon the Macronutrient Preference chosen, either fat or carbohydrates are set at a particular percent of calories (e.g. “Low-fat” is set at 20% calories from fat, and “Low-carb” is at 20% calories from carbs) to determine the allocation of the remaining non-protein calories.

4. Finally, the rest of the calories are filled out by the remaining macronutrient (either fat or carbs). Note, if “Balanced” was chosen, the non-protein calories are split evenly between fats and carbs.

In the weight loss calculator, you’ll see the terms “gentle,” “moderate,” and “strenuous.” These describe the intensity of your activity.

• Resistance training
• Interval or Circuit training
• Crossfit
• Running or jogging
• Rowing
• Cycling
• Swimming
• Team sports (e.g. basketball, hockey, soccer, tennis, etc.)
• Hiking
• Jump Rope
• Group classes (spin, dance, etc.) and bootcamps
• Yoga (power, bikram)

Examples of gentle activity include:

• Walking
• Yoga (hatha, vinyasa, ashtanga, etc.)
• Pilates
• Golfing
• Biking, swimming or cycling at a leisurely pace or for pleasure

Gentle activities are fantastic, but they don’t bump up your calorie needs like higher-intensity activity does. So it’s most important to count how many hours you spend engaged in moderate to strenuous exercise. When in doubt, it’s better to underestimate your activity rather than overestimate it.

Here’s an example. Let’s say your week includes:

• Walking for 20 minutes, 2 times
• Vinyasa yoga for 30 minutes, 2 times
• Resistance training for 45 minutes, 2 times
• Running for 30 minutes, 3 times

That’d count as:

• 4 gentle activities (vinyasa yoga x 2; walking x 2) for a total of 100 minutes (1.66 hours)
• 5 moderate to strenuous activities (resistance training x 2, running x 3) for a total of 180 minutes (3 hours)

Which means you’d select your activity level as “Moderate” under the purposeful exercise question. (Defined as moderate to strenuous activity 3 to 4 hours per week.)