Table salt, Morton kosher salt and Diamond Crystal kosher salt are equally salty gram for gram — they just pack into a teaspoon or cup very differently, because of their crystal shape. Convert between them by weight (exact) or by volume (approximate).
| Salt type | g/tsp | g/tbsp | Equivalent to 1 tsp table salt |
|---|---|---|---|
| Table salt | 6 g | 18 g | 1 tsp |
| Morton kosher salt | 5 g | 15 g | 1¼ tsp (some sources say up to 1½ tsp) |
| Diamond Crystal kosher salt | 3 g | 9 g | 2 tsp |
| Salt type | Weight per cup |
|---|---|
| Table salt | ≈290 g |
| Morton kosher salt | ≈240 g |
| Diamond Crystal kosher salt | ≈135–150 g (sources disagree — weigh it) |
Sodium chloride is sodium chloride: a gram of fine table salt delivers exactly the same amount of salty flavor as a gram of Morton kosher salt or a gram of Diamond Crystal kosher salt. What changes between them is entirely physical, not chemical — it's how each salt's individual crystals are shaped, and how much empty air ends up between them when you scoop a spoonful. Table salt is ground into small, dense, roughly cubic crystals that pack tightly with very little air between them. Morton kosher salt uses a flatter, flake-like crystal that leaves more air gaps. Diamond Crystal kosher salt goes further still: its crystals are formed as hollow, pyramid-shaped flakes through a different production process, so a cup or teaspoon of it is mostly air by volume compared to table salt.
That's why the same teaspoon measurement can hold such different weights: about 6 grams for table salt, about 5 grams for Morton kosher, and only about 3 grams for Diamond Crystal — roughly half the salt of table salt in the same volume. If a recipe says "1 tsp kosher salt" without specifying a brand and you use Diamond Crystal when the recipe was developed with Morton (or vice versa), you can end up 40-50% off on actual salt content, which is a meaningfully different level of seasoning. This is a well-known enough issue that serious recipe developers (including Diamond Crystal and Morton themselves) publish brand-specific conversion guidance rather than treating "kosher salt" as one interchangeable ingredient.
Diamond Crystal's cup weight is the one figure on this page we can't pin down precisely: published reference sources disagree with each other from about 135g to 150g per cup, likely because its hollow, flaky crystals compress unpredictably depending on how firmly they're packed into the cup. Rather than presenting a single false-precision number, this page shows that as a range and strongly recommends weighing Diamond Crystal on a scale instead of measuring it by cup whenever a recipe's salt content actually matters (bread doughs, brines, and precisely seasoned dishes especially).
The calculator above intentionally works in teaspoons, tablespoons and grams rather than cups, since the teaspoon-level weight figures are consistent enough to convert reliably — the cup-level uncertainty specifically affects volume measurements at that larger scale, so it's kept separate as a reference figure rather than folded into the live calculator.