Sodium Intake Calculator

About the Sodium Intake Calculator

The commonest error in this subject is treating salt and sodium as the same quantity. They are not, and the conversion between them is not a convention anyone chose — it falls out of the atomic masses.

Table salt is sodium chloride:

  Sodium:    22.99
  Chloride:  35.45
             ─────
  NaCl:      58.44

  Sodium is 22.99 ÷ 58.44  =  39.34% of salt by mass

Which gives salt = sodium × 2.542.

Read a sodium figure as though it were salt and you understate intake by about two and a half times. It happens constantly, because food labels in different countries quote different ones.

How to Use the Sodium Intake Calculator

Enter whichever figure you have — sodium (US labels) or salt (UK and EU labels). The calculator reports both.

Potassium is optional, and it matters more than most people realise.

Step-by-Step Example

3,400 mg of sodium a day — roughly the average US intake.

  3,400 mg sodium × 2.542  =  8,643 mg salt  =  8.6 g of salt

Against the limits:

  Upper limit  2,300 mg sodium  →  1,100 mg over
  Ideal target 1,500 mg sodium  →  1,900 mg over

The Same Limit, Stated Twice

This is why labels in different countries appear to disagree when they do not:

The well-known "6g of salt" guideline and the "2.4g of sodium" guideline are the same number. 6g of salt is 2,360mg of sodium; 2,400mg of sodium is 6.1g of salt.

Anyone comparing a UK label against a US guideline, or vice versa, without converting is out by a factor of 2.5 — and in the direction that makes intake look safe when it is not.

The Shaker Is the Smallest Lever

Here is the finding that should change what you actually do.

Roughly 70% of dietary sodium arrives already in the food, before anyone picks up a shaker. Only about 6% comes from the table.

So the intervention most people reach for first — cooking with less salt, taking the shaker off the table — addresses the smallest share of the problem. Reducing table salt by half changes total intake by about 3%.

What actually moves the number is what you buy. Bread, sauces, cured and processed meat, cheese, ready meals and restaurant food carry the overwhelming majority of it, and the variation between brands of the same product is often larger than anything you could do at the stove.

Sodium Is Half of a Ratio

The other thing rarely mentioned: sodium does not act alone.

Potassium works against it physiologically, and the sodium-to-potassium ratio predicts cardiovascular outcomes better than sodium alone. A ratio around 1:1 or lower is the general target.

Most people fail on both sides simultaneously — high sodium and low potassium — which means the ratio is worse than either figure suggests.

And raising potassium is frequently the easier half. It comes from vegetables, fruit, beans, potatoes and dairy, the target is around 3,500mg a day, and most people find adding those foods more sustainable than removing salt from everything.

Low Is Not Automatically Better

Worth stating, because public health messaging on sodium is uniformly directional.

Sodium is an essential electrolyte. Around 500mg a day is roughly the physiological minimum, and intakes well below that carry their own risks.

Anyone active, or living in a hot climate, loses substantial sodium in sweat and may genuinely need more than the general targets suggest. The advice to cut sodium is aimed at typical intakes well above the upper limit — it is not a universal instruction to go as low as possible.

The calculator flags very low intakes for that reason.

Why Sodium Matters at All

Worth a paragraph, because "eat less salt" is repeated far more often than it is explained.

Sodium is the main solute in the fluid outside your cells, and the body holds its concentration within a narrow range. Eat more sodium and the body retains more water to keep that concentration constant, which raises blood volume — and higher blood volume, over years, means higher pressure against the artery wall.

That is the mechanism, and it explains two things about the evidence. It explains why the effect on blood pressure is real but modest for most people, since healthy kidneys excrete the excess reasonably well. And it explains why some people respond far more than others: salt sensitivity varies considerably, is higher with age, and is higher in people who already have hypertension.

So the population-level advice to reduce sodium is sound while the individual-level effect is genuinely variable. If you have normal blood pressure and healthy kidneys, moving from 3,400mg to 2,300mg will do less for you than the messaging implies. If you are salt-sensitive or hypertensive, it will do considerably more.

Understanding Your Result

Sodium and salt gives both figures, so the conversion is never a question.

Why the factor is 2.54 derives it from the atomic masses.

Against the limits places you relative to both the upper limit and the ideal.

Where it comes from gives the source breakdown.

Worth knowing covers the ratio, the shopping point, or a very low intake.

When Should You Use This Calculator?

Reading a label from another country. The conversion is the whole point.

Comparing a guideline to a food. Check both are in the same unit first.

If you have been told to reduce salt. The shopping aisle matters more than the shaker.

Checking the ratio. Potassium is the half most people ignore.

Common Mistakes

Treating salt and sodium as interchangeable. They differ by 2.54 times.

Cutting table salt first. It is about 6% of intake.

Ignoring bread and sauces. They carry far more than anyone expects.

Forgetting potassium. The ratio predicts outcomes better than sodium alone.

Assuming lower is always better. Below about 500mg carries its own risks.

Comparing labels across countries without converting. One says sodium, the other says salt.

Sodium targets vary between health bodies and individual needs differ considerably — particularly for anyone with high blood pressure, kidney disease, or on medication affecting electrolytes. Nothing here is medical advice; discuss any significant change with a doctor.