A smaller sodium number on the front of a package is only useful when you know how much food it describes. Use this worksheet to compare the amount you plan to eat and, separately, an equal weight of two foods. The guide concerns US Nutrition Facts labels.
Copy the basis before the sodium number
The FDA explains that nutrition amounts usually refer to one serving, while some containers also show a whole-package column. A serving size reflects an amount people typically consume; it is not a recommended portion for you. Check the serving size, servings per container, and column heading first. [1]
Use the sodium amount in milligrams (mg) for the calculations below. Sodium appears on the Nutrition Facts label, as described by the FDA. This worksheet compares label figures and does not set a personal sodium target. [2]
An original fictional comparison
The two snack mixes below are invented for this exercise. They are not tested products, FDA examples, or shopping recommendations. Assume each package contains exactly the stated servings.
| Label information | Snack mix A | Snack mix B |
|---|---|---|
| Serving weight | 25 g | 40 g |
| Servings in package | 3 | 2 |
| Sodium per serving | 120 mg | 180 mg |
| Package weight | 75 g | 80 g |
| Sodium in entire package | 120 × 3 = 360 mg | 180 × 2 = 360 mg |
| Calculated sodium per 100 g | 120 ÷ 25 × 100 = 480 mg | 180 ÷ 40 × 100 = 450 mg |
A has the smaller per-serving figure. Both full packages contain the same calculated sodium amount, although their weights differ. B has the smaller figure at the shared 100 g basis. These are different questions; none of these results alone establishes overall food quality.
Calculate the portion you actually plan to use
For a fictional 50 g portion of A, divide the portion weight by the label serving weight: 50 ÷ 25 = 2 servings. Multiply that by the listed sodium: 2 × 120 = 240 mg.
For 50 g of B, the multiplier is 50 ÷ 40 = 1.25, giving 1.25 × 180 = 225 mg. This is a same-weight calculation. If you intend to eat different amounts of the two foods, calculate each actual portion separately instead.
Fill in your own comparison
| What to copy or calculate | Your product A | Your product B |
|---|---|---|
| Product name and label date | ___ | ___ |
| Label basis: serving or package | ___ | ___ |
| Serving weight, g | ___ | ___ |
| Sodium per serving, mg | ___ | ___ |
| Amount you plan to use, g | ___ | ___ |
| Portion multiplier: amount ÷ serving weight | ___ | ___ |
| Estimated portion sodium: multiplier × listed mg | ___ | ___ |
Check these limits before using the result
- If the label already gives sodium for the whole package, use that figure directly for a whole-package question. Do not multiply it by servings again.
- Keep mg separate from g. Do not mix a serving count with a package weight.
- Compare food in the same state, such as both dry or both prepared. Use any preparation instructions that change the label basis.
- Treat calculations from printed values as estimates; extra decimal places do not make the input more precise.
- Leave missing values unknown. A front-label claim is not a substitute for the Nutrition Facts information.
Sources and the scope of this worksheet
Source [1] supports the explanation of serving information and dual-column labels. Source [2] identifies the sodium information on US labels. All snack names, practice numbers, calculations, and blank comparison rows were created for this guide. The worksheet does not cover individual dietary restrictions or compare a food's overall nutritional value.