Celtic Salt Substitute: Swaps and Amounts

Out of Celtic salt? The right swap depends on whether you want its crunch on top of food or its saltiness inside it. For finishing, fleur de sel or Maldon flakes give you the crystals. For cooking, table salt works almost spoon for spoon: by the brand’s own label, a teaspoon of Light Grey Celtic weighs the same as a teaspoon of table salt, though it carries less sodium. Kosher salt is trickier, because the published conversions don’t agree.

“Celtic salt” usually means Celtic Sea Salt, a brand. Its Light Grey Celtic is a coarse gray sea salt, and the brand says natural brine stays in the salt, which keeps it moist.¹ The French call this style sel gris, gray salt.

Quick answer

What Celtic salt is doing	Best substitute	Starting amount, per 1 teaspoon Light Grey Celtic	Treatment
Finishing: crystals on steak, vegetables, salads	Fleur de sel, or Maldon flakes	By the pinch, to taste	Method
Seasoning while cooking	Table salt or fine sea salt	1 teaspoon by weight; a scant teaspoon by sodium	Computed
Seasoning while cooking, with kosher salt	Morton kosher	1 to 1¼ teaspoons	Disputed
Seasoning while cooking, with kosher salt	Diamond Crystal kosher	About 2 teaspoons	Disputed
A specialty salt with color	Coarse Himalayan pink salt	1 teaspoon by weight	Computed

How the ratios on this page are labeled

Computed: based on a measurable physical relationship.
Attributed: a named source publishes this ratio. We quote it as theirs.
Disputed: named sources give different answers to the same swap. You get each one, side by side.
Method: our starting point, based on how the two compare. Taste and adjust.

The gram figures for Celtic salt below come from the brand’s own Nutrition Facts panel, not an independent measurement. They’re for Light Grey Celtic, not every gray salt.

If Celtic salt is finishing a dish

Here it’s all about texture: big, slightly damp crystals that stay whole on the surface. America’s Test Kitchen recommends sea salts as finishing salts, scattered on food just before serving. ATK also found that sea salts vary in color but only slightly in flavor.²

1. Fleur de sel

Fleur de sel is the other salt from the same pans. The Guérande specification describes it forming as crystals floating in sheets on the surface, skimmed off by hand, while gray salt forms on the clay bottom and is harvested separately.³ Expect a whiter, cleaner-looking crystal without the gray.

Ratio (Method): Use it by the pinch and taste.

2. Maldon sea salt

Maldon gives you crunch in a different shape: thin, flat pyramid flakes. Those flakes break more easily than gray salt’s chunky crystals.

Ratio (Method): Use it by the pinch.

If Celtic salt is seasoning while you cook

Once salt dissolves into a soup, a sauce or pasta water, crystal shape stops mattering. America’s Test Kitchen notes that salt at its most basic is sodium chloride, whatever the source, and that sea salt tastes no different from table salt once it’s mixed into food.² What matters is how much salt is in the spoon.

How much salt is in a teaspoon

Light Grey Celtic’s label gives a ¼ teaspoon serving as 1.5 grams, with 480 mg of sodium.⁴ By our math, that’s 6.0 grams and 1,920 mg of sodium per teaspoon.

By weight, that’s the same as table salt. ATK weighs a teaspoon of table salt at about 6 grams, and Morton’s iodized table salt label also gives 1.5 grams per ¼ teaspoon.⁵⁶ By sodium, it’s lower. 480 mg in 1.5 grams is about 32 percent sodium, while the American Heart Association says table salt, kosher salt and most sea salts are about 40 percent sodium.⁴⁷ The label doesn’t explain the gap. Moisture could be part of it, since the brand says brine stays in its salt,¹ but we found no analysis that confirms it.

So there are two reasonable ways to convert, and they give different answers. Match by weight and you put the same number of grams of salt crystals in the pot. Match by sodium and you put in the same amount of sodium. Here are both.

Swap for 1 teaspoon Light Grey Celtic	Match by weight	Match by sodium	Sources
Table salt	1 teaspoon (6.0 g ÷ 6.0 g)	About ⅘ teaspoon (1,920 mg ÷ 2,325 mg)	⁵⁶⁸
Morton fine sea salt	About 1 teaspoon (label: 1.4 g per ¼ teaspoon)	No sodium figure retrieved	⁹
Morton kosher salt	1¼ teaspoons (6.0 g ÷ 4.8 g)	1 teaspoon (label: 480 mg per ¼ teaspoon, the same as Light Grey Celtic)	⁵¹⁰
Diamond Crystal kosher salt	About 2⅛ teaspoons (6.0 g ÷ 2.8 g)	No sodium figure retrieved	⁵
Morton coarse Himalayan pink salt	1 teaspoon (label: 1.5 g per ¼ teaspoon)	About ⅚ teaspoon (label: 570 mg per ¼ teaspoon)	¹¹
Fleur de sel, Maldon	No published gram figure	No published figure

The table-salt sodium figure is Tufts’ general number for a teaspoon of table salt, not a specific brand.⁸ Everything else comes from manufacturers’ labels and ATK’s weighings.

The kosher salt conversions disagree

Light Grey Celtic weighs the same per teaspoon as table salt, so converting it to kosher salt runs straight into a well-known disagreement over table salt itself:

Swap for 1 teaspoon table salt	Morton kosher	Diamond Crystal	Source
ATK’s rule of thumb	1½ teaspoons	2 teaspoons	²¹²
Morton’s conversion chart (Morton products only)	1¼ teaspoons	not covered	¹³
Computed from ATK’s gram weights (6.0 ÷ 4.8 and 6.0 ÷ 2.8)	1¼ teaspoons	about 2⅛ teaspoons	⁵

ATK’s own weights match Morton’s chart, not ATK’s rule of thumb.⁵¹³ We’re showing the disagreement instead of picking a winner.

Ratio (Disputed, with a starting point): For Morton kosher, start with 1 teaspoon per teaspoon of Light Grey Celtic. That’s the sodium match and the lowest figure. Taste before adding the next ¼ teaspoon. For Diamond Crystal, start at 2 teaspoons, the lowest of the figures above. If a recipe gives salt in grams, weigh it. ATK recommends weighing salt over measuring it by volume.¹²

If you want a specialty salt with character

Himalayan pink salt

Commercial Himalayan pink salt is rock salt from Pakistan, colored pink. Don’t count on it as a mineral supplement: a 2020 analysis of pink salts sold in Australia found that a 5-gram serving made no clinically significant contribution to nutrient intake.¹⁴

Ratio (Computed): One for one by weight. Morton’s coarse Himalayan label gives the same 1.5 grams per ¼ teaspoon as Light Grey Celtic.¹¹ Morton’s chart also treats a teaspoon of its Himalayan salt as equal to a teaspoon of table salt.¹³ Its label sodium is higher, so if you’re matching sodium, use a little less (see the table above).

Notes for every swap

Iodine. None of these salts is a reliable iodine source unless the label says iodized. The NIH Office of Dietary Supplements lists sea salt, kosher salt, Himalayan salt and fleur de sel among specialty salts that usually aren’t iodized.¹⁵ Celtic Sea Salt says it adds no iodine.¹
Sodium. Switching salts won’t lower your sodium unless you use less. A sea salt can carry less sodium per teaspoon just because fewer big crystals fit in the spoon.⁷ The FDA’s Daily Value for sodium is less than 2,300 mg a day.¹⁶
Moisture. Nothing reproduces gray salt’s dampness. If a recipe depends on it, a salt crust for example, use the gray salt the recipe was written for.

What isn’t known

We found no independent weight-per-teaspoon measurement of Light Grey Celtic. The 1.5-gram figure is the brand’s label, and a finer or drier grind would differ.
The brand’s label sodium (about 32 percent of weight) is lower than the roughly 40 percent typical of salt.⁴⁷ We found no analysis explaining why.
As far as we found, there’s no credible gram-per-teaspoon figure for fleur de sel or Maldon flakes.
You’ll often read that about 3 pounds of fleur de sel are harvested for every 80 pounds of gray salt. We found no source for it.

FAQs, Celtic Sea Salt (Selina Naturally). celticseasalt.com · Merchant ↩ ↩² ↩³
Salt Types and Measurements, America’s Test Kitchen. americastestkitchen.com · Publication ↩ ↩² ↩³
Cahier des charges de l’IGP Sel de Guérande / Fleur de sel de Guérande, French Ministry of Agriculture, 2025. info.agriculture.gouv.fr · Regulator ↩
Light Grey Celtic, product page, Celtic Sea Salt (Selina Naturally). celticseasalt.com · Merchant ↩ ↩² ↩³
Levine, The Best Kosher Salt, America’s Test Kitchen, 2019. americastestkitchen.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Morton Iodized Table Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩²
Sodium Sources: Where Does All That Sodium Come From?, American Heart Association, 2025. heart.org · Reference work ↩ ↩² ↩³
Tufts Health & Nutrition Letter, kosher salt Q&A, 2019. nutritionletter.tufts.edu · Publication ↩ ↩²
Morton Fine Sea Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩
Morton Kosher Salt Flakes, product page, Morton Salt. mortonsalt.com · Merchant ↩
Morton Coarse Himalayan Pink Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩²
Faithfull, The Wrong Brand of Kosher Salt Could Ruin Your Dinner, America’s Test Kitchen, 2022. americastestkitchen.com · Publication ↩ ↩²
Salt Conversion Chart, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³
Fayet-Moore et al., An Analysis of the Mineral Composition of Pink Salt Available in Australia, Foods, 2020. mdpi.com · Peer-reviewed ↩
Iodine: Fact Sheet for Health Professionals, NIH Office of Dietary Supplements. ods.od.nih.gov · Regulator ↩
Sodium in Your Diet, U.S. Food and Drug Administration. fda.gov · Regulator ↩

Also drawn on

About Celtic Sea Salt, Celtic Sea Salt (Selina Naturally). celticseasalt.com
Clear as crystal: the decades-old traditions of Maldon sea salt (Clare Finney, 23 Oct 2018), Foodism. foodism.co.uk

Celtic Salt Substitutes, with Teaspoon Conversions by Weight and Sodium