Read the top two lines before the sodium line

Every Nutrition Facts label opens with servings per container and serving size. On soup that pair does more work than anywhere else in the store, because cans differ in both size and concept.

Under FDA rules, a package holding less than twice the reference amount is labeled as a single serving. The reference amount for soup is 245 grams, a little under 9 ounces, so a 15 ounce can of ready to serve soup is labeled as one serving and the number you see is the number for the whole can. A 19 ounce can crosses that line and usually carries two columns, one per serving and one per container. Larger cartons show per serving information only, and the multiplying is left to you.

Condensed soup follows different logic. FDA's rules let a food that needs further preparation show nutrition information for the food as packaged and for the food as prepared, and the serving line may state how much prepared food that makes, such as a half cup of concentrate that makes 1 cup of soup. Read which version the numbers describe. A label reading "as prepared" already assumes you added water, so adding milk or broth instead changes the total.

Suppose a condensed can lists 1/2 cup condensed, about 2.5 servings per container, and 790 milligrams of sodium per serving. Emptying that can into a pot yields close to 2,000 mg, which is most of a day's Daily Value before anything else is eaten. The label never says that. You have to multiply.

The serving on a soup can is a legal reference amount, not a portion

Serving sizes are set by regulation from surveys of how much people typically eat, which makes similar foods comparable to each other. They are not advice about how much to eat, and they are frequently smaller than what ends up in a bowl. A separate article in this series works through serving size in detail.

The practical consequence for soup is that the per serving number can point the wrong way. Suppose Brand A lists 1 cup, 2 servings per container, and 590 mg of sodium. Brand B puts the whole 15 ounce can in one column at 780 mg. Brand B's number looks worse and the can is better: 780 mg for the container against 1,180 mg for Brand A.

Do the comparison at the level you eat. If you finish a can in one sitting, compare cans. If you split a can with someone, compare halves. Write the container total on the lid with a marker the first time you work it out, and the next trip takes no thought at all.

Condiments are measured in spoons, and the spoons are small

FDA's reference amounts explain why condiment labels look so mild. The current table sets these amounts:

1. 1 Major condiments, a group that includes ketchup, steak sauce, soy sauce, vinegar, teriyaki sauce, and marinades: 1 tablespoon.
2. 2 Minor condiments, including horseradish, hot sauces, mustards, and Worcestershire sauce: 1 teaspoon.
3. 3 Barbecue sauce, tartar sauce, tomato chili sauce, other sauces for dipping, and all dips: 2 tablespoons.
4. 4 Minor main entree sauces and other sauces used as toppings, such as gravy and cheese sauce, plus cocktail sauce: 1/4 cup.
5. 5 Major main entree sauces, such as spaghetti sauce: 125 grams, usually shown as about half a cup.

A teaspoon of mustard is a realistic squeeze. A tablespoon of soy sauce is not much once it is poured over a bowl of rice. The single most useful exercise in this category takes one minute at the kitchen counter: pour your usual amount of soy sauce, dressing, or barbecue sauce into a measuring spoon instead of onto the plate. Most people find they use two or three times the labeled serving, and every sodium figure on that label then needs to be doubled or tripled.

Government nutrient data shows how concentrated these products are. Regular soy sauce made from soy and wheat contains about 5,490 mg of sodium per 100 grams, which works out to roughly 880 mg in a tablespoon, close to 38 percent of the Daily Value. Tamari style soy sauce is similar at about 5,590 mg per 100 grams. For scale, the American Heart Association counts a quarter teaspoon of table salt as about 600 mg of sodium, so one tablespoon of regular soy sauce carries more sodium than that quarter teaspoon.

A reduced sodium condiment can still be a high sodium food

"Reduced sodium" and "less sodium" are comparisons, not levels. The regulation requires at least 25 percent less sodium than an appropriate reference food, and the label must identify that reference food, state the percentage difference, and print the actual milligram amounts being compared. Those milligram amounts are the numbers worth reading.

Apply that to soy sauce. The lower sodium soy sauce entry in the government nutrient database runs about 3,600 mg per 100 grams, roughly 575 mg in a tablespoon. That is a real cut of about a third, and it is still about 25 percent of the Daily Value in one tablespoon. Both statements are true at once, which is exactly the situation the claim is designed to describe and the reason the claim alone cannot end the comparison.

"Low sodium" is a different kind of claim, an absolute one: 140 mg or less per reference amount. For foods with small reference amounts, meaning 30 grams or less or 2 tablespoons or less, the food must also hold to 140 mg or less per 50 grams. That second test exists so a manufacturer cannot earn the claim by shrinking the serving. "No salt added" and "unsalted" describe what happened during processing, not the sodium in the finished food, and when such a food is not sodium free the package must carry a statement saying so. A separate article in this series covers the full set of claim definitions.

When the servings do not match, use per 100 grams

Two products in the same category usually share a reference amount, but sauces cross categories constantly, and gram weights vary even when the household measure looks identical. The fix is one division and one multiplication: sodium in milligrams divided by the serving weight in grams, times 100.

Suppose a jarred pasta sauce lists 480 mg of sodium in a 125 gram serving, and a jar of pesto lists 350 mg in a 60 gram serving. The pesto's number is lower. Per 100 grams the pasta sauce is 384 mg and the pesto is 583 mg, so the pesto is half again as salty spoon for spoon. Which one belongs in your cart depends on how much of each you use, and now you can reason about that instead of guessing.

One caution on precision. Sodium is rounded on labels: to the nearest 5 mg when a serving holds 5 to 140 mg, and to the nearest 10 mg above that. A 10 mg gap between two jars is inside the rounding and means nothing. Treat differences that small as a tie and decide on taste, price, or how the sauce is used.

Turning percent daily value into your own number

The percent Daily Value column gives a fast read. FDA's guide is that 5 percent DV or less of sodium per serving is low and 20 percent DV or more is high, measured against a Daily Value of less than 2,300 mg a day. In milligrams, 5 percent is about 115 mg and 20 percent is 460 mg.

The 2,300 mg figure is a labeling reference value, not a personal prescription. It matches the Dietary Guidelines for Americans, 2025 to 2030, which advises the general population ages 14 and above to consume less than 2,300 mg per day. The American Heart Association sets a stricter target, calling for no more than 2,300 mg a day with an optimal goal of no more than 1,500 mg for most adults, and says that for most people cutting back by 1,000 mg a day can improve blood pressure. The 2025 American Heart Association and American College of Cardiology high blood pressure guideline estimates that reducing sodium is associated with a drop of roughly 6 to 8 mm Hg in the top number in people who have high blood pressure.

If you and your care team have settled on a lower personal ceiling, the percent DV column is still usable with a small mental adjustment. Against a 1,500 mg target, everything is worth about half again as much: a serving at 20 percent DV is 460 mg, which is close to 31 percent of 1,500. A single condensed soup serving at 790 mg is 34 percent of 2,300 and 53 percent of 1,500. People with kidney disease, heart failure, or certain medicines may be given a different number entirely, which is a conversation for a health care professional rather than a label.

Soup you did not buy in a can

Deli soup, restaurant soup, and the pot at a lunch counter carry no Nutrition Facts label, and broth based soups are among the saltiest things on many menus. Chain restaurants and similar retail food businesses with 20 or more locations must post calories for standard menu items and must make written nutrition information available on request, and that written information includes sodium. Asking for it is ordinary and takes a moment. Many chains post the same figures online.

Independent shops have no such requirement. When you cannot get a number, the useful questions are simple ones: is the base a canned or boxed broth, is soy sauce or a seasoning blend added, and can the soup be served without the salted topping. A cup instead of a bowl is the other lever, and it is entirely in your hands.

Check again in a year

Recipes change. FDA issued voluntary short term sodium reduction targets for 163 categories of packaged and restaurant food in October 2021, aiming to bring average intake down to about 3,000 mg a day, and using 2022 data reported that roughly 40 percent of those targets had already been reached. A second set of draft targets issued in August 2024 proposes going further, to an average near 2,750 mg a day. The agency has said it will reassess progress about every three years.

For a shopper, that means the can you compared two years ago may hold a different amount of sodium today, in either direction. Recheck the few products you buy most often once a year, and recheck immediately if the packaging has been redesigned, since a new look often accompanies a new recipe.

One more thing worth noticing in the ingredient list on lower sodium soups and sauces: some replace part of the salt with potassium chloride. That is useful information rather than a warning for most people, but if you have kidney disease, or take a diuretic, an ACE inhibitor, an angiotensin receptor blocker, or another medicine that affects potassium, ask your health care professional or pharmacist before making potassium based products a regular habit.

Start with the two or three items you buy every week. A soup you eat twice a week, a sauce that goes on dinner most nights, and the bottle that sits on the table account for more sodium over a month than a dozen products you buy twice a year. Getting those right, with the container total written down and the tablespoon measured once, does most of the work.