Table Salt: What It Is, What’s Added to It, and Why It’s Iodized

Table salt is the salt in your shaker, and the one most American recipes mean when they just say “salt.” It’s fine-grained sodium chloride, about 40% sodium and 60% chloride by weight.¹ What sets it apart from kosher or sea salt isn’t the salt itself but the small, even grain and what gets added: usually an anticaking agent, and in iodized salt, iodine. Those fine grains pack tightly, so a teaspoon of table salt holds more salt than a teaspoon of most kosher or flaky salts. As for the iodine that often gets blamed for a metallic edge, America’s Test Kitchen’s tasters couldn’t tell iodized from noniodized salt.

At a glance

What table salt is

All food-grade salt is mostly sodium chloride. The Codex Alimentarius standard requires at least 97% sodium chloride on a dry-matter basis, not counting additives, whether the salt comes from the sea, rock deposits or natural brine.⁶ Table salt sits at the refined end of that range. It’s mined from salt deposits and processed to a fine, easy-mixing texture, which strips out other minerals. Its tiny, uniform crystals come from rapid vacuum evaporation, and it usually contains anticaking agents to help it pour smoothly.

In the United States in 2024, highway deicing alone used about 41% of the salt consumed. By type, US salt sold or used that year was 42% salt in brine, 40% rock salt, 9% solar salt and 9% vacuum pan salt. Worldwide, the USGS puts 2024 production at about 280 million tonnes, led by China (55 million), the United States (40 million) and India (28 million).⁷

What’s in the box

Check the ingredient list. Morton’s iodized table salt lists salt, calcium silicate (an anticaking agent), dextrose and potassium iodide.² Under US rules, salt with added iodide (as potassium or cuprous iodide) can be labeled “iodized salt” and has to carry the line “This salt supplies iodide, a necessary nutrient.” Plain salt has to say it doesn’t supply iodide. Salt with an anticaking agent can also be labeled “free flowing.”⁸

Flavor

Salt does more than make food taste salty. It also tamps down bitterness. In one 2010 lab study of taste mixtures, sodium chloride and sucrose together did most of the bitterness suppression.⁹ Salt also sharply cut perceived sourness in a 1967 study of salt and citric acid mixtures, tested in water and in a vegetable purée.¹⁰ Both tested solutions or simple mixtures, so they show which way the effect goes, not how it plays out in every dish.

Iodine often gets blamed for a bitter or metallic edge in table salt. ATK’s tasters couldn’t tell iodized from noniodized salt.¹¹ Where table salt really differs is texture and density. Its fine grains dissolve fast and pack tightly into a spoon, so a teaspoon of table salt holds more salt than a teaspoon of most kosher or flaky salts (see kosher salt for the numbers).

History

Salt has a long political history, though a lot of what gets repeated about it is hard to source. Two episodes are well documented:

• France. The gabelle was a tax in prerevolutionary France, and from the 15th century the word came to mean the salt tax specifically. People hated it enough that it turned up in the lists of grievances drawn up for the Estates-General of 1789, and it was abolished in March 1790.¹²
• India. The Salt March led by Mahatma Gandhi, also called the Dandi March, took place in Gujarat in March and April 1930. Britannica describes it as a major nonviolent protest and the first act of a larger civil disobedience campaign against British rule.¹³

Other stories you’ll see everywhere (that Greeks bought slaves with salt, supposedly giving us “not worth his salt,” that salt was worth its weight in gold in Rome, that Venice rose on a salt monopoly, that salt shaped the Lewis and Clark expedition and Civil War strategy) we couldn’t trace to a source we could open, so we’ve left them out.

How table salt is used

Table salt is the default for most cooking and nearly all baking. ATK makes it the go-to for most cooking because it dissolves easily. In baking, salt has to spread evenly through a dough or batter and gets measured by volume, so fine table salt is the predictable choice. Iodized and noniodized salt are interchangeable for flavor, going by ATK’s test.¹¹ For canning and pickling, you’ll want a pure salt without additives; see pickling salt.

Converting from table salt

Table salt is dense, so swapping in another salt by volume changes how much salt you’re adding. ATK gives 1 teaspoon of table salt as equal to 1½ teaspoons of Morton kosher salt or 2 teaspoons of Diamond Crystal. Morton’s own chart gives 1¼ teaspoons of its kosher salt. The sources disagree, and the kosher salt page lays out both. When in doubt, weigh it.

Storage

We couldn’t find a shelf-life figure for plain salt from a regulator or standards body. For iodized salt, the Codex standard includes storage precautions meant to limit iodine loss.⁶ Keep it dry and closed.

Iodine

Salt iodization programs have dramatically cut iodine deficiency worldwide. US salt makers have added iodine to table salt since the 1920s, and it’s still voluntary in the United States. US iodized salt contains 45 mcg of iodine per gram, and measured samples have averaged 47.5 to 50.7 mcg per gram. Adults need 150 mcg a day.³

Two catches. First, most salt in the American diet comes from processed foods, and manufacturers almost always use noniodized salt. If they do use iodized salt, they have to say so in the ingredient list. Second, specialty salts like sea salt, kosher salt, Himalayan salt and fleur de sel usually aren’t iodized. If you cook only with noniodized specialty salt, you’re getting little or no iodine from it. The ODS notes that noniodized sea salt provides virtually none.³

Internationally, the Codex standard says food-grade salt shall be iodized in iodine-deficient areas, at levels set by national health authorities.⁶ The WHO’s 2014 guideline covers fortifying food-grade salt with iodine to prevent iodine deficiency disorders, and the WHO recommends potassium iodate because it’s stable.¹⁴ About 88% of households worldwide now use iodized salt.³ For more, see iodized vs. non-iodized salt.

Sodium and health

Table salt is the yardstick for sodium advice. The FDA’s Daily Value for sodium is less than 2,300 mg a day, about a teaspoon of table salt, and Americans average about 3,400 mg.⁵ The AHA puts a teaspoon of table salt at 2,400 mg of sodium.¹ The WHO recommends adults stay under 2,000 mg of sodium (under 5 g of salt) a day and names raised blood pressure as the main health effect of eating too much.¹⁵

Older writing on salt sometimes claims table salt treats low blood pressure or that low salt intake causes type 2 diabetes. We found no regulator or systematic review backing either, and we don’t claim salt treats or prevents anything. Its established public-health role is as a carrier for iodine.³

Comparisons and related pages

• Kosher salt vs. table salt
• Table salt vs. sea salt
• Himalayan salt vs. table salt
• Rock salt vs. table salt
• Celtic sea salt vs. table salt
• Sea salt vs. iodized salt
• MSG vs. salt
• The best salt for cooking

If a dish has gone over, see too much salt or how to fix salty gravy.