Electrolyte calculator

Roughly how much sodium, potassium and magnesium a person needs a day on keto. In some cases only a doctor should set the amounts.

The numbers are estimates for healthy adults and do not replace medical advice or a diagnosis. If you have a condition, take medication, are pregnant or breastfeeding, talk to your doctor first. Read the medical disclaimer.

Phase

First weeks (adaptation)After adaptation

I sweat a lot (hard exercise or heat)I have high blood pressure, kidney or heart disease, or take blood-pressure medication or diuretics

Result

Sodium: 4,000–5,000 mg
Salt (equivalent): 10.0–12.5 g
Potassium (from food): 3,500–4,700 mg
Magnesium: 300–400 mg

No more than 250 mg of magnesium a day from supplements. Potassium supplements only on a doctor’s advice.

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How it is calculated

The ranges are daily totals from all sources (food, broth, salt), for healthy adults. Sodium 4–5 g in the first weeks or with heavy sweating, otherwise 3–4 g. Salt = sodium × 2.5.

Potassium 3.5–4.7 g a day from food (vegetables, avocado, nuts); potassium supplements only on a doctor’s advice. Magnesium 300–400 mg a day; no more than 250 mg from supplements (the EFSA upper limit).

With high blood pressure, kidney or heart disease, or on blood-pressure medication or diuretics, only a doctor should set sodium and potassium, so the tool gives no numbers.

Sources: EFSA, Dietary Reference Values for sodium and chloride (2019), potassium (2016) and magnesium (2015) · EFSA, Tolerable Upper Intake Levels for Vitamins and Minerals (2006) · Phinney SD, Volek JS, The Art and Science of Low Carbohydrate Living (2011).