# How to Read a Nutrition Label (Step by Step) > How to read a nutrition label step by step: serving size, calories, %Daily Value and the 5/20 rule, plus which nutrients to limit — or just scan the barcode. _Published 2026-07-10 · By LensNutra Team · LensNutra_ _Canonical: https://lensnutra.com/blog/how-to-read-a-nutrition-label_ To read a nutrition label, start with the serving size at the top, because every number below it describes one serving rather than the whole package. Then check the calories, use the Percent Daily Value column to judge each nutrient, and finish with the ingredient list. That order matters: almost every label-reading mistake comes from skipping the first step. Here is the full walkthrough, plus the one rule that makes the %Daily Value column readable at a glance. ## Key takeaways - Read the **serving size first**. Every calorie and gram on the label is per serving, and packages routinely hold two or three servings. - Use the **5/20 rule**: [the FDA](https://www.fda.gov/food/nutrition-facts-label/lows-and-highs-percent-daily-value-nutrition-facts-label) considers 5% DV or less per serving low in a nutrient, and 20% DV or more high. - **Limit** saturated fat, sodium and added sugars. **Prioritize** dietary fiber, vitamin D, calcium, iron and potassium. - **Added sugars** have their own line and a Daily Value of 50 grams, and they exclude sugars occurring naturally in milk, fruit and vegetables. - Ingredients are listed **by weight**, most to least, so the first three tell you what the food actually is. - For packaged food, [scanning the barcode](/features/barcode-scanner) captures the printed numbers exactly, with none of the arithmetic. ## What is a nutrition facts label? A nutrition facts label is the standardized panel on packaged food that lists the serving size, calories, and the nutrients in one serving of that food. Every value on it is per serving, not per package, and the Percent Daily Value column expresses each nutrient as a share of a daily reference intake based on a 2,000-calorie diet. That last detail is the one most people miss. The label is not describing what is in your hand. It is describing a portion the manufacturer defined, measured against a hypothetical 2,000-calorie day that may be nothing like yours. ## How to read a nutrition label, step by step ### 1. Start with the serving size The serving size and "servings per container" sit at the very top of the panel, and they govern everything printed underneath. A bag of chips listing 150 calories may contain three servings, which makes the bag 450 calories. Serving sizes are standardized so you can compare two products fairly, but they are not a recommendation of how much to eat. They only tell you what the numbers below refer to. ### 2. Adjust for how much you actually eat If you eat two servings, double every number on the label, including the %DV. If you eat half a serving, halve them. This single correction fixes the most common label mistake, and it is where most accidental calorie surplus hides. ### 3. Check the calories per serving Calories tell you how much energy one serving supplies. Multiply by the servings you actually ate. The label's Percent Daily Value figures assume a 2,000-calorie day, which is a reference point rather than a target — your own number depends on your body and activity, and you can estimate it with our [calorie calculator](/tools/calorie-calculator). ### 4. Use %Daily Value and the 5/20 rule The Percent Daily Value column converts grams and milligrams onto one 0-to-100 scale so you can compare products without math. To read it quickly, use the rule the FDA publishes: 5% DV or less of a nutrient per serving is considered low, and 20% DV or more per serving is considered high. So you want a *low* %DV on the things to cut, and a *high* %DV on the things to get more of. A cereal with 25% DV of fiber is high in fiber. A soup with 30% DV of sodium is high in sodium, and that is one of three bowls' worth of your day's sodium in a single serving. ### 5. Limit some nutrients, prioritize others The [American Heart Association](https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/understanding-food-nutrition-labels) frames the panel the same way: use %DV to choose foods lower in saturated fat, sodium and added sugars, and higher in fiber, vitamin D, calcium, iron and potassium. The federal [Dietary Guidelines for Americans](https://www.dietaryguidelines.gov/) likewise build healthy patterns around limiting added sugars, saturated fat and sodium. ### 6. Read the ingredient list Below the panel, ingredients appear in descending order by weight. The first three or four ingredients are most of what you are eating. If a sweetener, a refined grain or an oil leads the list, that is the food's real identity, whatever the front of the box claims. ## Which nutrients to limit vs. get more of The panel is really two lists in one. Use the 5/20 rule in opposite directions for each. | Nutrient | Limit or get more? | Target %DV per serving | Why it matters | | --- | --- | --- | --- | | Saturated fat | Limit | 5% DV or less | Linked to higher risk of heart disease | | Sodium | Limit | 5% DV or less | Raises blood pressure risk across the diet | | Added sugars | Limit | 5% DV or less | Adds calories with no added nutrients | | Trans fat | Avoid | No DV listed; look for 0 g | No known safe level of intake | | Dietary fiber | Get more | 20% DV or more | Improves fullness and digestive health | | Vitamin D | Get more | 20% DV or more | Commonly under-consumed | | Calcium | Get more | 20% DV or more | Bone health; commonly under-consumed | | Iron | Get more | 20% DV or more | Carries oxygen in the blood | | Potassium | Get more | 20% DV or more | Offsets sodium's effect on blood pressure | Protein has a %DV only on some labels, because deficiency is rare in most diets. That does not mean protein is unimportant for you — if you are tracking body composition it is the macro that matters most, which we cover in [how to track macros](/blog/how-to-track-macros). ## Added sugars and the updated label The FDA's redesigned Nutrition Facts label added a separate "Added Sugars" line beneath total sugars. It matters because total sugars lump together the lactose in plain milk and the cane sugar in a candy bar, which are not nutritionally equivalent. Per the [FDA](https://www.fda.gov/food/nutrition-facts-label/added-sugars-nutrition-facts-label), the Daily Value for added sugars is 50 grams per day based on a 2,000-calorie daily diet, and added sugars exclude the sugars naturally present in milk, fruits and vegetables. A single sweetened drink can use most of that allowance, which is exactly what the separate line is there to reveal. ## How to read the ingredients list Two products can post near-identical panels and be entirely different foods. The ingredient list is where that shows up. - **Order equals weight.** The first ingredient is the largest by weight, the last is the smallest. - **Sugar wears many names.** Cane syrup, dextrose, fruit juice concentrate, maltose and honey are all added sugars. Split across three names, sugar can sit lower in the list while still dominating the product. - **Shorter is not automatically better.** A long list can just mean added vitamins. Read what the ingredients *are*, not how many there are. The panel tells you how much. The ingredient list tells you what. ## Reading labels for weight loss and macros For weight loss, the label answers one question: how many calories am I about to eat, really? Serving size, then calories, then multiply by what is actually on your plate. Fiber and protein are worth prioritizing because they keep you full at a given calorie count, which makes a deficit easier to sustain. If you are unsure what your deficit should be, start with [how many calories to lose weight](/blog/how-many-calories-to-lose-weight). Whole foods have no label at all. A chicken breast, an apple, a cup of rice — for those, a reference database such as [USDA FoodData Central](https://fdc.nal.usda.gov/) or a per-food page like our [calorie guides](/calories) is the equivalent, and [photographing the plate](/blog/how-to-count-calories-from-a-photo) is faster than either. ## Skip the squinting: scan the barcode instead Reading labels well is a genuinely useful skill, and it is also slow. Doing the serving-size multiplication for every packaged item, every day, is exactly the friction that ends most tracking attempts by the second week. That is why label reading and label *scanning* solve different halves of the problem. [Scanning a barcode or the label itself](/features/barcode-scanner) pulls the printed numbers in exactly as written — no arithmetic, no misread serving size — and drops them into a running daily total. For anything without a barcode, [the AI food scanner](/features/ai-food-scanner) estimates from a photo, and [the macro tracker](/features/macro-tracker) keeps protein, carbs, fat and fiber in view as the day fills up. Learn the label so you can judge a product in the aisle. Scan it so you actually log it. ## The bottom line Read the label in this order: serving size, servings per container, calories, then the %DV column with the 5/20 rule in mind — low for saturated fat, sodium and added sugars, high for fiber, vitamin D, calcium, iron and potassium. Then check the first three ingredients to see what the food really is. Do that once per new product and you never have to do it again for that product. Better yet, [scan it once](/download) and let the numbers land in your day automatically.