Electrolyte Calculator

What they actually do

Sodium, potassium and magnesium carry an electrical charge once dissolved, and that charge is the whole point of them. Sodium is the main mineral outside your cells and largely sets how much water your body holds, which is why sodium and hydration are the same conversation. Potassium does the equivalent job inside the cell, and the difference in charge across the cell membrane is what lets a nerve fire, a muscle contract, and then let go again. Magnesium sits inside hundreds of enzyme reactions, including several tied to that relaxation step. You lose all three in sweat, sodium by a wide margin.

When topping up genuinely matters

Usually it does not. Normal food with salt on it covers a normal day, and plain water is fine for a normal session. The cases that earn a top-up are narrow and easy to recognize: work past about an hour, especially in heat, heavy sweaters who finish training with salt crusted on their kit, and low-carb or keto eating, which pushes sodium out faster. Outside those, an electrolyte sachet is mostly a flavored way to drink water. No harm in that, it is just not doing much.

A worked example

Say you are moderately active, in a temperate climate, an average sweater, eating normally. The tool lands on roughly 1,913 to 2,588 mg of sodium a day, 2,610 to 3,390 mg of potassium, and 315 to 426 mg of magnesium. Those are whole-day totals, not workout doses, and food does most of the lifting: a medium potato is about 900 mg of potassium, a quarter teaspoon of salt about 575 mg of sodium. Move that same person to a hot climate as a heavy sweater and the sodium band climbs to about 3,615 to 4,890 mg, which is the estimate reacting to sweat loss rather than a number to chase with powder.

Reading a sports drink honestly

A standard sports drink is mostly sugar with a little sodium, and that formula was built for endurance athletes who need the carbohydrate as much as the salt. For a 45 minute lifting session it is a soft drink with a sports logo on it. For two hours in the heat, the sugar is doing real work. Judge it against the session you are actually doing. If you want the minerals without the sugar, tablets and unsweetened powders cover the same three, and salted food plus water covers them for nothing.

The honest limits

These are population intake ranges nudged by your answers, not a measurement of you. Sweat sodium varies enormously between people, and none of it is visible from a form. Cramp is the thing everyone wants electrolytes to solve, and the evidence there is genuinely muddy: fatigue and unfamiliar workloads look like at least as large a factor. If cramping keeps happening, or you notice anything past ordinary thirst, that is a doctor's question rather than a calculator's. The same goes for anyone with kidney or heart concerns, on blood pressure medication, or pregnant. Nobody should be moving their sodium around based on this page. For the fluid side of it, the water intake calculator and the sodium intake calculator pick up where this one stops.