How much sodium is in a teaspoon of salt?

About 2,330 milligrams. The USDA record for table salt has 38,800 mg of sodium per 100 g, and a teaspoon weighs 6 g. The FDA describes its 2,300 mg daily limit as about 1 teaspoon of table salt.

How do I calculate sodium per serving in a recipe?

Find the sodium in each ingredient, add them together and divide by the number of servings. Most of it usually comes from two or three lines: the salt itself, salty sauces, cheese, and baking soda or baking powder.

What counts as low sodium?

On a food label the FDA allows 'low sodium' at 140 mg or less per serving, 'very low sodium' at 35 mg or less, and 'sodium-free' at less than 5 mg. As a general guide, 5 percent of the Daily Value or less per serving is low and 20 percent or more is high.

Does baking soda add sodium?

Yes. Baking soda has about 1,260 mg of sodium per teaspoon and baking powder about 490 mg, by USDA figures. In baking they can add as much as the salt does.

Is unsalted butter really lower in sodium?

Yes. USDA lists salted butter at 643 mg of sodium per 100 g and unsalted at 11 mg. Half a cup of salted butter adds about 730 mg to a recipe, and half a cup of unsalted about 12 mg.

Sodium per Serving Calculator for Recipes

Milligrams of sodium per teaspoon and per tablespoon, from USDA weights and values
Ingredient	Sodium per teaspoon	Sodium per tablespoon	Sodium per 100 g
Salt	2,328 mg	6,984 mg	38,800 mg
Baking soda	1,260 mg	3,781 mg	27,400 mg
Baking powder	488 mg	1,463 mg	10,600 mg
Soy sauce	293 mg	878 mg	5,490 mg
Fish sauce	471 mg	1,413 mg	7,850 mg
Ketchup	51 mg	154 mg	907 mg
Mustard, yellow	55 mg	165 mg	1,100 mg
Parmesan, grated	30 mg	90 mg	1,800 mg
Butter, salted	30 mg	91 mg	643 mg
Butter, unsalted	1 mg	2 mg	11 mg
Peanut butter	23 mg	68 mg	426 mg
Tomato paste	3 mg	9 mg	59 mg

How the calculator works

The calculator reads each line of your recipe, matches it to a food in USDA FoodData Central, converts the amount to grams and applies the USDA sodium figure:

sodium in a line = grams / 100 x sodium per 100 g

sodium per serving = total sodium / servings

Sodium is counted in milligrams. The figures per 100 g run from 0 for sugar and oil up to 38,800 mg for table salt, so a recipe’s sodium is nearly always decided by a few small, strong ingredients. Open “Show the math” to see each line’s share.

Worked example

A butter cake: 2 cups flour, 1/2 cup salted butter, 3/4 cup sugar, 2 eggs, 1 teaspoon baking powder, 1/2 cup milk and 1/4 teaspoon salt. It makes 12 pieces.

Salted butter, 113.5 g: 730 mg
Salt, 1/4 teaspoon (1.5 g): 590 mg
Baking powder, 1 teaspoon (4.6 g): 488 mg
Eggs, 100 g: 142 mg
Milk, 122 g: 52 mg
Flour, 250 g: 5 mg
Sugar, 150 g: 2 mg

Total: 2,008 mg. Per piece: 2,008 / 12 = 167 mg.

Look at the order. The quarter teaspoon of salt is only the second largest source. The butter adds more, and the baking powder adds nearly as much. Three lines account for 90 percent of the sodium, and none of them would be called a salty ingredient in a sweet cake.

Make the same cake with unsalted butter and the butter line falls from 730 mg to 12 mg. The total drops to 1,290 mg, or 108 mg a piece, a cut of 36 percent from one swap.

Where sodium hides

From the USDA records the calculator uses:

Per teaspoon

Table salt: 2,328 mg
Baking soda: 1,260 mg
Baking powder: 488 mg
Fish sauce: 471 mg
Soy sauce: 293 mg

Per tablespoon

Fish sauce: 1,413 mg
Soy sauce: 878 mg
Salted butter: 91 mg
Grated parmesan: 90 mg
Unsalted butter: 2 mg

A tablespoon of soy sauce is a little over a third of a teaspoon of salt. A tablespoon of fish sauce is 60 percent of one. In a stir-fry with 3 tablespoons of soy sauce, the sauce alone is 2,635 mg of sodium before any salt is added.

Leavening is the one that surprises people. Baking soda is sodium bicarbonate, and a teaspoon of it carries more than half the sodium of a teaspoon of salt.

Reading the result

The FDA’s Daily Value for sodium is 2,300 mg, and its page on sodium describes that as about 1 teaspoon of table salt. Its general guide for any nutrient is:

5 percent of the Daily Value or less per serving is considered low. For sodium that is 115 mg.
20 percent or more per serving is considered high. For sodium that is 460 mg.

The cake at 167 mg a piece is 7 percent. A stir-fry serving with 660 mg from soy sauce alone is 29 percent.

The FDA also defines the claims you see on packaged food, which are useful reference points for a home recipe:

Sodium-free: less than 5 mg per serving
Very low sodium: 35 mg or less per serving
Low sodium: 140 mg or less per serving
Reduced sodium: at least 25 percent less than the regular product

According to the same FDA page, Americans eat about 3,400 mg of sodium a day on average, and over 70 percent of it comes from packaged and prepared foods. A recipe you cook yourself is one of the few places you can see every source.

Why your number may differ

Kinds of salt. The calculator uses the USDA record for table salt, at 6 g per teaspoon. Coarse and flaky salts weigh less per teaspoon, so a recipe made with them has less sodium than the same spoon measure of table salt. Enter salt in grams if you can.

Brands. Soy sauce, stock, canned tomatoes and cheese vary a great deal between brands and between regular and reduced sodium versions. The label on your bottle beats an average.

Salted water. Salt added to pasta or blanching water is counted in full if you list it, though most of it goes down the drain. Leave it out of the list, or accept that the figure is high.

Salt to taste. The calculator cannot count it. Measure what you add once, then enter that amount.

Rinsing. Canned beans are listed as canned. Draining and rinsing them changes the sodium, and the calculator does not model that.

Tips and common mistakes

Check the butter line first. Salted against unsalted is the biggest single swap in most baking.

Count every sauce. Soy sauce, fish sauce, ketchup and mustard are all concentrated sources.

Do not forget the leavening in baked goods.

Divide by real servings. A sauce that “serves 4” but is shared by two doubles the sodium each.

Compare versions. Change one ingredient, re-run it, and see what the swap is worth in milligrams.

Sodium per Serving Calculator