Kosher Salt vs. Table Salt: The Conversion Mistake That Ruins Dishes

The mistake that can nearly double a dish's saltiness

A home cook switches from table salt to kosher salt — maybe following a chef's recommendation, maybe just because it's what was in the cabinet — and measures salt into a dish the same way they always have, teaspoon for teaspoon, cup for cup. The dish comes out under-seasoned, or in the reverse switch, wildly over-salted, and the cook has no idea why, because they used the "same amount" of salt either way.

The problem is that "the same amount" by volume is not the same amount by actual salt content, because different salt types have dramatically different crystal structures — and crystal structure, not chemistry, is what determines how much salt fits into a teaspoon or a cup.

Why crystal shape changes how much salt is in a spoonful

Table salt is refined down into small, uniform cubes that nest together with almost no wasted space when poured into a measuring cup — pack that many tightly-fitted crystals into one cup and you end up with 288 grams of salt, among the heaviest common ingredients this site tracks by volume.

Kosher salt takes a completely different shape on purpose — coarser, more irregular flakes that a cook can pinch and feel between their fingers while seasoning by hand, which is exactly the tactile quality professional kitchens value it for. The trade-off is that those bigger, oddly-shaped flakes stack loosely, leaving real air gaps a fine cubic crystal wouldn't leave — so a cup of it holds noticeably less actual sodium chloride than the same cup filled with table salt, identical chemistry aside.

Diamond Crystal, one of the two dominant US kosher salt brands, comes in at just 128 grams per cup — under half of table salt's figure for the identical cup. Morton, the other major brand, lands in between at 241 grams per cup: heavier than Diamond Crystal's flakes, but still short of table salt's tightly packed weight.

The actual conversion ratios, and which direction they go

Converting FROM table salt TO Diamond Crystal kosher salt means using roughly double the volume — about a 2:1 ratio, using twice as much Diamond Crystal by volume to match table salt's saltiness. This is the direction that trips people up most often, because the instinct is to assume more of a coarser-looking salt must be excessive, when it's actually correcting for how much less salt that same volume contains.

Converting FROM table salt TO Morton kosher salt uses a smaller adjustment — roughly 1.25:1 by volume, since Morton's crystals are denser than Diamond Crystal's, closer to (though still not equal to) table salt's density.

Going the other direction — substituting table salt for a recipe written around kosher salt — means using significantly LESS table salt than the recipe's kosher salt measurement specifies, roughly half as much for a Diamond Crystal recipe, since table salt packs so much more actual salt into the same volume.

Why professional recipes so often specify kosher salt by brand

This is also why serious recipe writing has increasingly started naming a specific brand — "Diamond Crystal kosher salt" or "Morton kosher salt" — instead of the generic "kosher salt." Both sit on the same supermarket shelf under the same category name, but swap one for the other at an equal volume and you're not making the equivalent substitution the label implies.

A recipe developed and tested with Diamond Crystal, if followed with an equal volume of Morton instead, would end up meaningfully saltier than intended, since Morton packs nearly double Diamond Crystal's salt mass into the same cup. This isn't a hypothetical edge case — it's common enough that professional kitchens and serious recipe developers treat the brand distinction as load-bearing information, not a minor detail.

The most reliable way to sidestep the whole problem

Put salt on a scale and the crystal-shape problem disappears entirely — mass doesn't care whether the grains are cubic or flaky. Anywhere salt quantity is genuinely load-bearing to the outcome — bread dough, a brine, a cure — weighing it is the version of this conversion worth trusting over eyeballed spoonfuls.

For ordinary stovetop cooking where pulling out a scale mid-recipe isn't realistic, the more practical habit is simply knowing which salt a recipe was built around, and adjusting on purpose with the ratios above rather than assuming a spoon of one salt equals a spoon of another. Unlike most substitutions on this site, this one has nothing to do with flavor or texture changing — it's purely a measurement problem, and the only thing that matters is getting the direction of the ratio right.

Does this same crystal-size problem apply to other salts?

Sea salt and finishing salts (flaky salts like Maldon) introduce their own crystal geometry, generally even more irregular and larger than either kosher salt brand, which means they typically pack even less densely by volume than either table salt or standard kosher salt — a reasonable default assumption, though this site doesn't carry a sourced density figure for every specialty salt on the market, and treats an ingredient without a reliable figure as out of scope rather than guessing.

Pickling and canning salt, by contrast, is closer to table salt in crystal structure — small and uniform, without the anti-caking additives sometimes found in table salt — which makes it a reasonably close volume match for table salt, unlike the kosher salt comparison this guide focuses on.

The broader lesson holds regardless of which specific salt you're working with: crystal size and shape, not the chemical identity of the salt, is what determines how much fits in a spoon or a cup. Any time a recipe or a swap involves changing which physical form of salt you're using, it's worth pausing to ask whether the volume conversion actually holds — table salt to kosher salt is simply the most common version of that question home cooks run into.

A practical checklist for the next time a recipe just says 'salt'

Check whether the recipe names a specific salt type or brand at all — if it does, that's a strong signal the recipe developer tested and calibrated the dish around that exact product, and substituting a different salt without adjusting the quantity is departing from what was actually tested.

If no salt type is specified, table salt is the more common default assumption in most published home recipes, simply because it's the most widely owned salt in a typical household pantry — though professional and chef-authored recipes increasingly default to kosher salt instead, which is part of why checking the source matters.

When genuinely unsure and the dish is forgiving (a soup, a stew, most savory cooking), season conservatively and taste as you go rather than trusting any fixed conversion ratio blindly — salt is one of the few ingredients where correcting a slight under-seasoning mid-cook is easy, while correcting an over-salted dish is often not.