How to Read Nutrition Labels With Your Phone [In Store]
Nutrition labels are printed small and laid out in ways that make comparison hard. Use your phone to zoom in at 3x to 4x, then compare products using the per 100 g column rather than per serving, since serving sizes differ between brands. Check the ingredients list for sugar under other names, and remember that sodium on a label is converted to salt by multiplying by 2.5.
Why nutrition labels are hard to read
Two problems make labels hard: the print is small, and the numbers are not set up for comparison. One cereal box lists a serving as 30 g, another as 45 g, and the columns may use different units. A phone camera fixes the first problem, and the per 100 g column fixes the second.
Getting the panel readable
Nutrition panels are often printed in 6 to 8 point type, sometimes on a curved surface, sometimes in dark gray on a colored background. In a store, this works quickly:
- Open a magnifier app and zoom to 3x or 4x. That makes the panel look like normal print, and the image stays steady at that level.
- Hold the package so the panel faces you and is as flat as possible. For cans and bottles, rotate the container rather than moving the phone.
- Turn on the flashlight if the panel is on dark packaging or the shelf lighting is poor. If it glares off plastic film, dim it: in LoupeLens, press and hold the flashlight button and slide down.
- Tap the screen to take a photo when the panel is in view. Then put the package down, pinch into the photo, and compare it with a photo of the second product.
Comparing two photos on screen is faster than flipping two boxes back and forth, and you can look at them again at home.
Per 100 g versus per serving
If you change one habit, make it this one. Serving sizes are chosen by the manufacturer and vary widely between brands of the same product. A product can look lower in sugar per serving simply because it declares a smaller serving.
Most labels include a per 100 g (or per 100 ml for drinks) column, and in many countries, including the EU and UK, it is required. US Nutrition Facts labels show per-serving values only; to compare products, divide each value by the serving size in grams. Use the per 100 g figures when comparing two products, because they are directly comparable no matter how each package defines a portion.
Per serving is still useful for estimating what you actually eat. If the serving is 30 g and you pour 60 g, double everything.
Finding the sugar
The nutrition panel gives total sugar, and often added sugar separately. The ingredients list tells you where it comes from. Ingredients are listed in descending order by weight, so anything in the first three is a major component.
Sugar appears under many names. When scanning an ingredients list, treat any of these as sugar:
- Sucrose, glucose, dextrose, fructose, maltose, lactose (anything ending in -ose)
- Corn syrup, high-fructose corn syrup, glucose syrup, rice syrup, golden syrup, maple syrup, agave
- Honey, molasses, treacle
- Fruit juice concentrate, fruit puree concentrate
- Cane sugar, brown sugar, raw sugar, coconut sugar, invert sugar
- Barley malt, malt extract
A product can split its sweetener across several of these so that no single one ranks first. If you see three or four sugar names spread through the list, add them up mentally. Maltodextrin is not labeled as sugar, but it is a fast-digesting starch and worth noticing for the same reason. As a rough conversion, 4 g of sugar is about one level teaspoon.
Sodium and salt are not the same number
Some labels list sodium, others list salt, and a few list both. Salt (sodium chloride) is only about 40 percent sodium by weight, so the conversion is:
Salt in grams = sodium in milligrams x 2.5 / 1000
| Sodium on label | Equivalent salt |
|---|---|
| 100 mg | 0.25 g |
| 400 mg | 1.0 g |
| 600 mg | 1.5 g |
| 1000 mg | 2.5 g |
A label that says 0.5 g salt per 100 g and another that says 200 mg sodium per 100 g are showing the same amount. Bread, breakfast cereal, sauces, and cured meat are where this comparison matters most.
Other lines to check
Fat and saturated fat
Total fat gets the attention, but saturated fat is usually the line health guidance focuses on. Check both, per 100 g.
Fiber
For bread, cereal, and crackers, fiber per 100 g separates whole grain products from ones that are only brown in color. Compare fiber alongside sugar, since the two often move in opposite directions.
Percent daily values
These are based on a reference adult and a reference serving. They give a rough sense of high or low, but they do not help when comparing two products with different serving sizes. Use per 100 g for that.
Claims on the front
"Reduced sugar", "light", and "no added sugar" have specific meanings that vary by country, and none of them means low in sugar. A "no added sugar" juice is still mostly sugar. Read the panel, not the front.
A quick routine for the aisle
- Pick up both products and find the nutrition panel on each.
- Zoom in and photograph each panel.
- Compare sugar, saturated fat, salt (or sodium x 2.5), and fiber, all per 100 g.
- Glance at the first three ingredients.
- Choose. Once it is a habit, this takes under a minute.
If you read labels for medical reasons, such as managing blood sugar or blood pressure, the same routine works, and keeping photos of the products you trust makes them easy to find again. If allergies are the concern, our allergen shopping guide goes deeper, and for the ingredient list itself see reading ingredient lists in the store. To decode the best-before or use-by code on the same package, see how to read expiration date codes.
Reading panels at home
At home you have more time and better light, so check the products you buy regularly. Once you know that your usual bread has 1.1 g salt per 100 g, you can compare a new one against it in seconds in the store. A few photos of your regular products, taken at 3x, make a handy reference to carry on your phone.
Frequently asked questions
Should I compare nutrition labels per serving or per 100 g?
Per 100 g or per 100 ml. Serving sizes are set by the manufacturer and differ between brands, so per-serving numbers are not comparable. The per 100 g column puts every product on the same scale. US Nutrition Facts labels show per-serving values only, so divide each value by the serving size in grams to compare products.
How do I convert sodium to salt on a food label?
Multiply sodium in milligrams by 2.5 to get salt in milligrams, then divide by 1000 for grams. For example, 400 mg sodium is 1 g salt. Salt is roughly 40 percent sodium by weight, which is where the factor comes from.
What are the hidden names for sugar in ingredients?
Anything ending in -ose (glucose, dextrose, fructose, maltose, sucrose), any syrup (corn, glucose, rice, golden, maple), honey, molasses, fruit juice concentrate, cane sugar, coconut sugar, invert sugar, and barley malt. Maltodextrin is not labeled as sugar but is a fast-digesting starch. Several may appear in one list so that no single one ranks near the top.
What zoom should I use to read a nutrition label with my phone?
Around 3x to 4x is enough for the typical 6 to 8 point nutrition panel and keeps the image steady. Turn on the flashlight if the panel is on dark packaging, and take a photo so you can compare two products side by side.
Does 'no added sugar' mean low in sugar?
No. It means no sugar was added during manufacturing, but the product can still be high in naturally occurring sugar. Fruit juice and dried fruit products are common examples. Check the total sugar per 100 g on the panel.