How do you calculate a nutrition score? Your comprehensive guide

October 11, 2025 •

5 min read

Approximately 11 million deaths worldwide in 2017 were linked to unhealthy diets, emphasizing the need for clear tools to guide food choices. Understanding how do you calculate a nutrition score can empower consumers to navigate complex food labels and make better purchasing decisions for improved health.

Quick Summary

This guide details the methods behind different food scoring systems used to evaluate a product's nutritional value. It explains the formulas for popular labels like Nutri-Score, Nutrivore Score, and EWG's Food Scores to help simplify food comparisons.

Key Points

Positive vs. Negative Components: Most scores, like Nutri-Score, are calculated by offsetting points for high-level nutrients (energy, sugar, fat, salt) against points for beneficial ones (fiber, protein, FVLN).
Standardized per 100g/ml: To ensure comparability, systems like Nutri-Score standardize their calculations to a consistent quantity of 100 grams or 100 milliliters.
Nutrient Density Approach: The Nutrivore Score focuses on nutrient density, measuring the ratio of total nutrients to total calories for a more comprehensive view of nourishment.
Multi-factor Evaluation: Beyond just nutrients, EWG's Food Scores consider ingredient concerns and the level of processing, offering a broader assessment of a product's overall health quality.
Comparison is Key: Nutrition scores are most useful for comparing similar food products within the same category rather than judging the entire diet based on one label.
Consider the Limitations: Context is vital, as a high score on one system doesn't mean a product is perfect for everyone, and some healthy foods might be penalized by certain algorithms.

Introduction to Nutritional Scoring

Nutrient profiling systems are designed to classify or rank foods based on their nutritional composition, providing a simplified visual summary for consumers. Instead of requiring a deep dive into the mandatory nutrition facts panel, these scores offer an at-a-glance snapshot of a food's healthiness. Various systems exist, each with its own methodology, but they all share the fundamental goal of translating complex nutritional data into an easy-to-understand format. By focusing on a balance of beneficial and less-desirable nutrients, these scores can guide healthier choices and even motivate manufacturers to reformulate their products.

The Nutri-Score System

The Nutri-Score is a voluntary, five-color front-of-package labeling system first adopted in France in 2017 and used across several European countries. It assigns a color and a letter—from dark green 'A' (most healthy) to dark orange 'E' (least healthy)—to products based on a calculation per 100 grams or 100 milliliters. The final score is determined by balancing "negative" points, given for ingredients to limit, against "positive" points, for ingredients to favor.

Step-by-Step Nutri-Score Calculation

To calculate the Nutri-Score for a product, you must first gather the nutritional information from the label. The process involves four main steps:

Allocate Negative Points (N): A product receives points for its content of calories (energy), saturated fat, total sugars, and sodium per 100g/ml. A scoring table assigns 0 to 10 points for each of these four components based on their amount. The total N points are the sum of these values.
Allocate Positive Points (P): Points are then awarded for favorable nutritional elements: protein, dietary fiber, and the percentage of fruits, vegetables, legumes, and nuts (FVLN). A separate scoring table assigns up to 5 points for fiber, up to 7 for protein, and up to 5 or 6 points for FVLN depending on the amount.
Calculate the Final Score: The total positive points (P) are subtracted from the total negative points (N). The formula is: Nutri-Score = Total N points - Total P points. There are specific algorithmic variations for certain food types, such as beverages, fats, and cheeses.
Determine the Final Grade: The final numerical score is converted to a letter grade (A-E) using a set range. For instance, a score of 0 or less typically receives an 'A', while a score of 19 or higher gets an 'E'.

The Nutrivore Score

Another approach is the Nutrivore Score, which measures nutrient density—the total nutrition a food delivers per calorie. Instead of just considering a few negative and positive factors, it evaluates over 30 essential and important nutrients relative to their daily values. The score is calculated by summing the percentage of daily values for these nutrients per 100 grams and then dividing by the food's energy density (calories). This method provides a comprehensive picture of how nourishing a food truly is, rather than just highlighting a few components. A higher Nutrivore Score indicates more nutrients packed into every calorie.

EWG's Food Scores

EWG's Food Scores offer a different, multi-faceted approach, providing an overall rating from 1 (best) to 10 (worst). The overall score is calculated by combining three separate scores:

Nutrition: This is the most heavily weighted component and is based on a modified version of the UK's Food Standards Agency profiling system. It considers factors like calories, saturated fat, sugar, sodium, protein, and fiber.
Ingredient Concerns: This score flags potential health or environmental concerns related to additives, contaminants, pesticides, hormones, and antibiotics.
Processing: This score rates the extent to which a food product has been processed, based on factors like ingredient modification and the number of artificial ingredients.

By including these three elements, EWG's system aims to provide a more holistic view of a food product's quality beyond just its basic nutritional values.

Comparing Popular Nutrition Scoring Systems


Feature	Nutri-Score	Nutrivore Score	EWG's Food Scores
Primary Goal	Simplify comparison within food categories.	Measure nutrient density (nutrients per calorie).	Assess nutritional value, processing level, and ingredient safety.
Key Factors	Energy, saturated fat, sugars, sodium, protein, fiber, FVLN.	30+ essential and important nutrients.	Nutrition, ingredient concerns, processing.
Calculation Basis	Balance of negative and positive points per 100g/ml.	Sum of % daily values divided by calorie density.	Weighted combination of three separate scoring factors.
Focus	Front-of-pack label for quick comparison.	Comprehensive nutrient density evaluation.	Overall product quality, including non-nutritional aspects.
Output	Color-coded letter grade (A-E).	Numerical score.	Numerical score (1-10) with three sub-scores.

Limitations and Considerations

While nutritional scores are valuable tools, it is crucial to understand their limitations. A single score can sometimes oversimplify the complexity of nutrition. For example, a healthy food like olive oil might receive a lower Nutri-Score (like a D) due to its high calorie and saturated fat content, even though it is beneficial in moderation. Some systems also do not account for the level of food processing, which is a key factor in overall health. Furthermore, personal dietary needs and health conditions are not reflected in a universal score. Therefore, using these scores as a quick guide for comparison between similar products is most effective, but they should not override common sense and broader dietary knowledge. For example, comparing two types of breakfast cereals using a Nutri-Score is a valid application, but comparing a cereal to a cheese is not.

Conclusion

Knowing how to calculate a nutrition score reveals the intricate algorithms that simplify complex food choices. Whether it's the A-E grade of Nutri-Score, the nutrient density ratio of Nutrivore, or the multi-factor evaluation of EWG, each system provides a different lens through which to view a food product's health profile. By understanding the methodology behind these scores, consumers can make more informed decisions at the grocery store. These tools are valuable aids in a health-conscious lifestyle, encouraging smarter swaps and a more balanced diet.

foodwatch.org - Nutri-Score: how to use a label to improve health and diet

Glossary of Terms

Nutrient Profiling System (NPS): A method used to evaluate and rank foods based on their nutritional composition.
Nutrient Density: The concentration of beneficial nutrients in a food relative to its calorie content.
Daily Value (DV): The recommended intake levels for a nutrient, often used as a benchmark in nutrition calculations.
Front-of-Package Labeling (FOPL): Simplified, interpretive symbols or scores placed on the front of food packaging to provide nutritional information.

Frequently Asked Questions

The easiest method is to use an online calculator provided by the specific scoring system, such as those available for the Health Star Rating System or Nutrivore Score databases. For Nutri-Score, you can perform the manual calculation using the values from the product's nutrition panel and the official algorithm tables.

To manually calculate the Nutri-Score, you must first assign 'negative' points for energy, saturated fat, sugars, and salt per 100g/ml. Then, assign 'positive' points for fiber, protein, and fruit/vegetable/nut content. Finally, subtract the positive points from the negative points to get the final score, which is then mapped to a letter grade from A to E.

The specific factors vary by system. The Nutri-Score considers calories, saturated fat, sugars, sodium, protein, fiber, and the percentage of fruits, vegetables, and nuts. Other systems like EWG's Food Scores also evaluate processing levels and potential ingredient concerns, like additives and pesticides.

No, it is not recommended. Nutrition scores are designed to help you compare similar products within the same category (e.g., one breakfast cereal to another) but not across different categories like dairy and soup. This is because the context and composition are vastly different.

Not necessarily. While a high score (like an 'A' on Nutri-Score) indicates a generally better nutritional profile within its category, it doesn't account for all health aspects or individual dietary needs. Context matters, and some naturally healthy foods may get lower scores due to an algorithm's limitations.

The Nutrivore Score is a measurement of nutrient density, meaning it quantifies the nutrients a food provides relative to its calorie content. It is calculated using over 30 nutrients, which offers a more comprehensive view than systems focused on just a few key factors.

Olive oil, despite its health benefits, receives a less favorable Nutri-Score (often a 'D') primarily because the algorithm penalizes its high content of saturated fat and calories, without fully factoring in the quality of the fats. This is a key limitation showing why context is important.

In some systems, yes. EWG's Food Scores specifically include a 'Processing' factor to reflect the extent to which a food has been modified. The Nutri-Score algorithm does not directly evaluate processing levels, a common criticism of the system.