The formula
How to calculate sodium intake
Salt and sodium are not the same thing, and food labels use both. Salt is sodium chloride; sodium is roughly 39% of it by weight, which is why the two figures differ by a factor of about 2.5.
UK guidance sets a maximum of 6 g of salt a day for adults, equivalent to about 2,360 mg of sodium. The World Health Organization recommends less than 5 g of salt, or 2,000 mg of sodium.
What to enter:
- Salt eaten per day (g)
No submit button: type and the answer moves. Your inputs end up in the link, so the page can be shared already filled in.
Consistency in how the underlying measurements are taken matters more than precision to the last decimal — measuring at the same time of day, in the same state of rest or hydration, makes readings taken weeks apart genuinely comparable in a way that a single very precise reading on its own is not.
Why sodium intake matters
People usually look up a sodium intake calculation to put a number on something they can already sense but cannot quite quantify — how their fitness compares with a reference range, how a measurement is trending, or what a change actually means. A calculator turns that vague sense into a concrete figure, which is useful even though the figure itself is only ever an estimate.
It is most useful tracked over time rather than read once — a single reading tells you where you are today, while the same calculation repeated weeks or months apart, using the same method each time, shows the direction things are actually moving in.
None of the figures produced on this page are intended to replace a proper assessment, and nothing here should be read as a diagnosis or a treatment recommendation. What a calculator like this is good for is preparation — arriving at an appointment with an actual number already in hand, rather than a vague sense of a change, tends to make that conversation more useful for everyone involved.
A calculator like this one is frequently used to prepare a specific number for an upcoming appointment, so that a description like "I think it has changed" can be replaced with an actual figure and a date it was measured on. Clinicians and trainers generally find a concrete number, however approximate, more useful to work from than a general impression.
Worked example
Take the figures the calculator starts with:
- Salt eaten per day: 8.4 g
That gives:
- Sodium: 3,304.56 mg
- Share of the 6 g daily salt limit: 140 %
- Salt above the limit: 2.4 g
Those starting figures exist only to show the calculation working, not as a target or a reference value to compare yourself against — replace them with your own measurements in the calculator above and the same formula applies exactly as shown.
Reading the result
Average UK intake is around 8.4 g a day, roughly 40% above the limit. Most of it — about three quarters — comes from processed food rather than the salt cellar, so label reading achieves more than cooking differently.
Where this goes wrong. Comparing a sodium figure on one label against a salt figure on another. Always convert to the same unit first; a "low sodium" claim can still sit alongside a substantial salt content.
As with any general-purpose formula, the result here is an estimate derived from population averages, not a measurement specific to you — a reasonable starting point for a conversation with a qualified professional, not a replacement for one. Nothing on this page is medical advice.
About 5 g of salt, or a level teaspoon. The conversion is sodium in grams times 2.5.
No. The sodium content is essentially identical, and the trace minerals in sea salt are present in quantities too small to matter nutritionally.
It returns sodium. With 8.4 g salt eaten per day, that comes to 3,304.56 mg. Change any field and the figure moves with it.
It uses a published formula applied exactly as defined, so the arithmetic itself is precise — but the formula is a population-level estimate, and individual results can vary from it for reasons the formula has no way to account for. Treat the output as a reasonable estimate rather than a measured or diagnostic value.
For most people, yes — a single reading is a snapshot, while the same measurement repeated consistently over weeks or months shows a trend, which is generally more informative than any one figure taken in isolation.
Small differences between calculators usually come down to which published formula or reference dataset each one uses — several equations in this area exist in more than one accepted version. This page states the specific formula used in the section above, so it is possible to check directly whether another source is using the same one.