How to convert sodium to salt (and salt to sodium)

Written by Catherine Saxelby on Friday, 06 August 2010.
Tagged: food labels, guides, measures, MSG, salt

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As a nutritionist, my aim is to help busy women eat healthily. One of the ways to do this is to follow the general nutrition advice to reduce the salt in your diet. So, how can you do this when what you’ll see on a food label and on any recommended daily intakes is sodium?

What’s the difference between salt and sodium?

Chemically salt is sodium chloride which is made up of one atom of sodium plus one atom of chlorine. While half the salt molecule is sodium, it’s not half by weight. You can’t just halve the weight of salt to find your sodium intake. Sodium is roughly 40 per cent of the weight of salt, with chlorine the remaining 60 per cent.

Sodium chloride molecule Reversed In tiny quantities, both sodium and chlorine are essential for health and growth. The problem today is we eat way too much sodium.

Two ways to convert

To help you, I've put together my quick converter table in Step 1 or else use the handy rules in Step 2.

1. Quick sodium and salt converter table

Salt in grams	Sodium in mg	This is roughly equivalent to	Nutrition cut-offs
1	400	Good pinch of salt
1.25	500	One-quarter of a teaspoon salt
2.3	920	One-third of a teaspoon salt	Lower limit of the RDI
2.5	1000	Half a teaspoon salt
4	1600	¾ of a teaspoon salt
5	2000	One teaspoon salt	Aim for this as your maximum day's intake
6	2400	1¼ teaspoons salt	Upper limit of the RDI
10	4000	2 teaspoons salt
12	4800	2½ teaspoons salt	Average intake upper end

So, 5 grams of salt is equal to 2000mg of sodium, both of which are contained in one teaspoon of salt.
If a recipe calls for one teaspoon of salt and serves 4 people, you're getting one-quarter of a teaspoon of salt from it or around 500mg sodium per serve.

2. Use the conversion rules

To convert the sodium to salt or salt to sodium, use these rules:

Sodium to salt

To convert sodium to salt, multiply the sodium figure in milligrams (mg) by 2.5 and then divide by 1,000. So:

milligrams of sodium x 2.5 = milligrams of salt

Divide by 1,000 to convert to grams of salt

Example
200mg of sodium
200mg x 2.5 = 500mg salt ... then divided by 1,000 = 0.5 grams salt
So 200mg of sodium equates to 500milligrams or 0.5 grams of salt

Salt to sodium

To convert grams of salt to milligrams of sodium

Divide the salt figure in grams by 2.5 and then multiply by 1,000 to get milligrams.

grams of salt ÷ 2.5 = grams of sodium

grams of sodium x 1,000 = milligrams of sodium

Example
6 grams of salt
6g ÷ 2.5 = 2.4g salt ... then multiplied by 1,000 = 2400 mg of sodium
So 6 g of salt equates to 2400 milligrams of sodium

How much sodium is too much?

Our sodium intake should be less than 2,300 mg per day, roughly a teaspoon (or 6 grams) of salt. Ideally, getting your sodium to less than 1600 mg per day is even better as it can help prevent ill health later in life. I suggest you use the mid-point figure of 2,000 mg sodium as a convenient figure to remember.

However, the average daily intake is somewhere between 6 to 12 grams of salt (or 6,000 to 12,000 milligrams) which roughly equates to 2,300 to 4,600 milligrams of sodium. This means we're consuming double the amount we need.

Sodium - what's low?

Less than 120 mg sodium per 100 grams is a low sodium food. These are unsalted foods such as unsalted butter, unsalted margarine, canned tomatoes with no added salt and fresh produce like vegetables, fruits, nuts, milk, fish, meat, eggs, oils, rice, pasta, couscous, pearl barley and other grains.

Sodium - what's high?

More than 600 mg sodium per 100 grams is a high sodium food. This can vary from category to category e.g. any bread under 400 mg is considered acceptable, but for salty sauces anything under 1000 mg is a good achievement.

Other forms of sodium apart from salt

A food may contain NO salt (sodium chloride) but may still be high in sodium because of the presence of naturally-occurring sodium (as in celery or spinach) or other sodium containing ingredients and additives such as:

Baking powder Baking soda	Sodium bicarbonate
Flavour enhancer	MonoSodium Glutamate (MSG)
Preservatives	Sodium benzoate, sodium nitrite, sodium sulphite
Antioxidant	Sodium ascorbate (the sodium salt of ascorbic acid or Vitamin C). You'll see this as an additive in many white wines under the additive code No 300

Compare high, medium and lower salt foods

Look at these three categories of similar foods divided into the high, medium and lower category e.g corn flakes (highest in salt) vs weet-bix (medium) vs oats (lower). You will see the same gradation for baked goods such as croissants and crumpets and for soups.

Sodium category	Food	Serve	mg sodium per serve	g salt per serve
	Breakfast cereal
High - over 600 mg per 100 g	Kellogg’s Corn Flakes	1 metric cup, 35 g	169	0.4
Medium - between 120 and 600 mg per 100 g	Sanitarium Weetbix	2 biscuits, 30 g	81	0.2
‘Lower’ - less than 400 mg per 100 g but see note below *	Uncle Toby’s rolled oats	1 serve, 40 g uncooked	2	Less than 0.1
	‘Breads’
High	Croissant	1, 57 g	424	1.1
Medium	Golden crumpet	1, 50 g	300	0.8
‘Lower’	Sunblest white bread	2 slices, 60 g	250	0.6
	Soup/stock
High	Campbell’s Chicken Stock	1 cup, 250 ml	1,118	2.8
Medium	Continental Chicken Noodle soup	1 cup, 250 ml, 1 packet makes up 4 serves	685	1.7
‘Lower’	Home-made chicken stock, no added salt	1 cup, 250 ml	230	0.6
Suggested daily maximum			2000	5

Figures taken from food labels as at 2020

* We have classed these items as "low" compared to other products. However, some of these do not meet the official government definition of less than 120 mg per 100 grams. However they are all under 400 mg per 100 g.

Editor's note: This article was updated in August 2020. Catherine Saxelby aims to help busy women eat healthily and keep up-to-date on the latest nutrition information. Sodium levels in general have reduced since this article was first published and the latest figures have been added to the tables.