Salt to Sodium Converter
Convert between salt and sodium, and see what it means against your own region’s guidance.
This converts between two units. The daily figures below are published guidance for healthy adults, quoted with their source — they are not medical advice, and they do not apply to children, whose recommended limits are lower and vary by age. If you are on a prescribed salt or fluid restriction, follow that instead.
What this tool does
Multiply sodium by 2.5 to get salt; divide salt by 2.5 to get sodium. That factor exists because sodium is about 40% of the weight of salt and chlorine is the rest. So 1,000 mg of sodium is 2.5 g of salt — which is already close to half a day under most guidance.
Converts salt to sodium and back, using either the label factor or the exact chemistry.
Shows what the amount represents against the UK, EU, WHO and Australian daily figures at once, and gives the front-of-pack traffic light band.
How to use it
- Enter the figure from the label and pick grams or milligrams.
- Read the converted value, the working underneath it, and the bar showing the share of a daily guideline.
- For the traffic light colour, enter the salt per 100 g as well.
Why use this converter
Some labels list salt and others list sodium, and the two differ by a factor of about 2.5, so a figure of "1 g" can mean very different amounts. Converting makes products comparable and relates them to daily guidance.
Why we built it
We built the salt to sodium converter to show the daily guidance for several regions side by side, since the UK, WHO and EU figures are not the same. Convert energy on the same labels with the kJ to calories converter and weights with the ounces to grams converter.
For a neighbouring job there is also the Steps to Miles Converter, the Oven to Air Fryer Converter and the Weight & Mass Converter.
Who this tool is for
- People following a low-sodium diet
- Shoppers comparing labels that list salt or sodium
- Health students
When to use it
- Comparing a salt label with a sodium label.
- Checking a food against a daily guideline.
- Reading the traffic-light band on UK packaging.
- Following a doctor's advice given in one of the two units.
Where 2.5 comes from
It is chemistry, not a rule of thumb.
Table salt is sodium chloride. Sodium has a molar mass of about 22.99 and the whole compound about 58.44, so sodium is 22.99 / 58.44 = 39.34% of salt by weight. Chlorine is the other 60.66%.
The reciprocal of 0.3934 is 2.542. Labelling rounds that to 2.5, which is the factor you will see quoted everywhere.
This tool offers both. The label factor is what regulators and packaging use; the exact factor is what the chemistry gives. They differ by 1.7%, which is irrelevant on a sandwich and worth being able to see rather than having it silently applied.
The rounding is slightly generous: dividing by 2.5 reports about 1.7% more sodium than the exact chemistry does. It errs toward caution.
Why labels disagree about which to show
UK and EU labels are required to state salt. US, Australian and New Zealand labels state sodium. Same food, same substance, different number on the packet — which is the entire reason this conversion is needed.
The practical consequence is that a sodium figure looks smaller than the equivalent salt figure by a factor of two and a half, and it is easy to read an American label as low-salt when it is not.
A US label showing 500 mg of sodium per serving is 1.25 g of salt — about a fifth of a UK adult daily figure, in one serving.
Daily guidance differs by region
Which is why this shows several at once.
There is no single worldwide number, and a converter that quietly picks one is wrong for most of the places its readers live.
| Region | Authority | Salt per day | Sodium equivalent |
|---|---|---|---|
| UK | NHS | 6 g | about 2.4 g |
| EU | EFSA | 5 g | about 2.0 g |
| Worldwide | WHO | 5 g | about 2.0 g |
| Australia and NZ | NHMRC | 6 g (suggested target) | about 2.4 g |
These are figures for healthy adults. Children’s recommended limits are lower and banded by age, and are not shown here rather than shown approximately.
They are also guidance published by those bodies, quoted as such. They are not this tool’s claims, and anyone on a prescribed restriction should follow that instead.
The traffic light is per 100 g
UK front-of-pack colour coding is calculated on grams per 100 g, not per serving. That distinction catches people out constantly.
| Band | Salt per 100 g |
|---|---|
| Green — low | 0.3 g or less |
| Amber — medium | over 0.3 g up to 1.5 g |
| Red — high | over 1.5 g |
A small pack of something very salty can carry an amber or even green light on the per-serving figure while being red per 100 g. The colour describes the food; the per-serving number describes the portion the manufacturer chose.
What you give it, and what you get back
| Item | Details |
|---|---|
| Input | A salt or sodium amount in grams or milligrams. |
| Optional | Salt per 100 g to see the traffic-light band. |
| Output | The converted value, the working and the share of UK, EU, WHO and Australian daily figures. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| Factor looks like 2.5 vs 2.54 | Labels use 2.5; chemistry gives 2.542. | Choose label or exact mode. |
| Guidance seems different | Regions publish different daily limits. | Check the body named beside each figure. |
| Medical advice expected | This is a unit converter. | Follow your clinician's advice. |
Assumptions and limitations
- Converts between units. It does not know what is in your food, and nothing here is dietary or medical advice.
- Daily figures are for healthy adults. Children’s limits are lower, age-banded, and deliberately not shown.
- Guidance changes. Each figure names the body that published it so you can check the current version at source.
- Assumes the sodium in the food is from sodium chloride. Sodium from additives such as sodium bicarbonate converts on the same mass basis but is not "salt" in the culinary sense.
- Traffic light bands are the UK scheme. Other countries use different front-of-pack systems entirely.
Frequently asked questions
How do I convert sodium to salt?
Multiply sodium by 2.5. To go the other way, divide salt by 2.5. So 1,000 mg of sodium is 2,500 mg — 2.5 g — of salt.
Why multiply by 2.5?
Because sodium is only part of salt. Sodium chloride is 39.34% sodium by weight and 60.66% chlorine, and the reciprocal of that fraction is roughly 2.5.
Is it 2.5 or 2.542?
The chemistry gives 2.542; labelling rounds it to 2.5. The difference is 1.7% and immaterial for food, but this tool offers both rather than rounding without telling you.
How much salt a day is recommended?
It depends where you are. The NHS says 6 g for UK adults; the WHO and EFSA say 5 g. Both are shown here with their source, because there is no single worldwide figure.
Why do some labels show sodium and others salt?
Different rules. UK and EU labels must state salt; US, Australian and New Zealand labels state sodium. It is the same substance measured two ways, and the sodium figure always looks smaller.
What do the traffic light colours mean?
On UK front-of-pack labels: green is 0.3 g of salt per 100 g or less, amber is up to 1.5 g, red is above that. Crucially it is per 100 g, not per serving, so a small portion of a very salty food can still be red.
Does this apply to children?
No. The figures shown are for healthy adults. Children have lower limits that vary by age, and they are deliberately not included here rather than being approximated.
Sources and accuracy
Molar masses of Na and NaCl; label factor per NHS/FSA and EU guidance
Figures last checked against the source on . Standards and rates can change — if you are relying on this for something that matters, confirm against the source above. Think a figure is wrong or out of date? Send a correction.
Further reading
Kilojoules, calories, salt and sodium: reading a food label — Two conversions that trip people up on food labels: kilojoules to calories, and salt to sodium. The exact factors, and why sodium looks smaller than salt.