Table Salt vs. Sea Salt: Grain, Iodine, Minerals and How to Swap Them

Table salt and sea salt are the same stuff, sodium chloride, and the American Heart Association puts both at about 40% sodium by weight.¹ Sea salt is what’s left when seawater evaporates. Table salt is mined from deposits and processed to a fine texture, which strips out other minerals.¹ Once it’s mixed into food, sea salt tastes no different from table salt in America’s Test Kitchen’s testing.² The differences that matter in your kitchen are the crystal size, which decides how much salt fits in a spoon, and iodine, which most sea salt doesn’t have.³

Side by side

How each is made

The Codex standard for food-grade salt covers salt from the sea, from rock deposits and from natural brine, and requires at least 97% sodium chloride on a dry basis, not counting additives, wherever it comes from.¹⁰ Table salt sits at the refined end. ATK says its tiny, uniform crystals come from rapid vacuum evaporation, and that it usually carries an anticaking agent so it pours smoothly.² Under US rules, salt with an anticaking agent can be labeled “free flowing.”¹¹

Sea salt is made by evaporating seawater, by sun for Morton’s fine sea salt⁵ or over heat for Maldon’s flakes.¹² The AHA describes it as usually unprocessed or lightly processed.¹ Some sea salts get their color from something physical. Under the French specification for Guérande salt, the gray salt is gray from fine clay picked up off the pan floor.¹³

Minerals and iodine

Minerals. Sea salt may carry trace amounts of magnesium, potassium and calcium,¹ but when you measure them, they’re tiny. In a 2016 survey by Switzerland’s food safety office, six of seven sea salts bought in shops or online had potassium below 0.05 g per kg, and the report concluded that specialty salts have no advantage over standard salt.⁸

Iodine. Here’s the real nutritional difference. US salt makers have added iodine to table salt since the 1920s, voluntarily, at 45 mcg per gram. The NIH Office of Dietary Supplements lists sea salt among specialty salts that usually aren’t iodized.³ In the Swiss survey, sea salts carried at most 54 µg of iodine per kg,⁸ more than 800 times less than the US iodized label, by our math.

The ODS says most of the US population gets enough iodine, though many pregnant women may not, and names seafood, eggs, milk and milk products among the best food sources.³ Most of the salt in the American diet comes from processed foods, which almost always use noniodized salt.³ So if you switch from iodized table salt to sea salt at home, you’re dropping one of the few dependable iodine sources you control. See sea salt vs. iodized salt.

Flavor and texture

ATK found that sea salts vary in color but only a little in flavor, and once mixed into food taste the same as table salt, so it recommends sea salt mainly for finishing.² Its tasters also couldn’t tell iodized from noniodized salt.²

You’ll often hear that sea salt tastes “saltier” or “stronger” because its bigger crystals linger on the tongue. We found no test backing that up. What big crystals definitely do is crunch, and they hold less salt in a spoon, because fewer of them fit.¹

Salt’s effects on flavor apply to both. In lab taste studies, sodium chloride together with sugar did most of the work of suppressing bitterness in taste mixtures,¹⁴ though that was a test of simple solutions, not real dishes.

Can one stand in for the other?

Yes. By weight they’re interchangeable. By volume, match the crystal. These swaps follow our sea salt substitute page.

How we got these. By weight: Codex sets at least 97% sodium chloride on a dry basis for food-grade salt from any source.¹⁰ By volume: Morton’s chart treats a teaspoon of its table salt as equal to a teaspoon of its fine or coarse sea salt, with only a teaspoon’s difference at a full cup (1 cup of table salt equals 1 cup plus 1 teaspoon of fine sea salt). That holds for Morton products only.¹⁵ Its labels agree: 1.5 g per ¼ teaspoon of iodized table salt against 1.4 g for both sea salts,⁴⁵⁷ about 7% apart by our math. A rule you’ll see everywhere, 1¼ teaspoons of sea salt per teaspoon of table salt, doesn’t fit those figures for fine or coarse sea salt, and we couldn’t find a source for it. Flaky salts pack loosely, and we didn’t find a published weight per teaspoon for any of them. The ½-teaspoon start borrows the cautious figure from our Maldon salt substitute page. It’s a starting point, not a measurement.

Which to use when

• Table salt: anything you measure by the spoon, baking, brines and the shaker, and your everyday salt if you count on salt for iodine. Morton markets its iodized salt for cooking and baking.⁴
• Sea salt: finishing, as ATK recommends,² and fine sea salt anywhere you’d use table salt.

A sensible split: iodized table salt for cooking and a flaky sea salt for finishing.

Health notes

• Sodium. Weight for weight, it’s the same. Table salt and most sea salts are about 40% sodium, and the AHA says total sodium intake is what matters most for heart health.¹ The FDA’s Daily Value for sodium is less than 2,300 mg a day, about a teaspoon of table salt.¹⁶ A coarse sea salt has less sodium per teaspoon only because fewer crystals fit.¹
• Microplastics. In a 2018 study of 39 salt brands, reported in a Greenpeace press release, contamination was highest in sea salt, then lake salt, then rock salt.¹⁷ The release gives no figure for refined table salt. It’s one study of specific products, not the whole market.
• Health claims. Neither salt treats or prevents anything. Iodized salt’s established role is as a carrier for iodine.³

What isn’t known

• No test showing sea salt tastes saltier than table salt, weight for weight.
• No published weight per teaspoon for flaky sea salts, or for any sea salt beyond Morton’s labels.
• No figure for how much iodine iodized salt loses sitting in a home pantry.
• No dated, sourced price comparison.

Related

• Table salt and sea salt, the full profiles
• Sea salt substitutes
• Sea salt vs. iodized salt, iodized vs. non-iodized salt, kosher salt vs. table salt and kosher salt vs. sea salt
• Himalayan salt vs. table salt, Celtic sea salt vs. table salt and rock salt vs. table salt
• Cooking with sea salt, too much salt and MSG vs. salt