Daily Sodium Intake Calculator
Two different things get confused here. The 2,300 mg figure is a daily ceiling for blood-pressure reasons. Sweat replacement is additional, session-specific, and only relevant if you actually sweat a lot.
Your results
General information, not medical advice. If you have a medical condition, are taking medication, or are pregnant, speak to a doctor rather than acting on a number from a web page. Sweat sodium concentration varies enormously between individuals — from roughly 0.5 g to over 2 g per litre — and the categories above are self-assessed.
Sodium is the only electrolyte worth replacing
Per litre of sweat you lose roughly:
- Sodium: around 1,000 mg (0.5–2 g depending on the person). The one that matters.
- Chloride: around 1,500 mg — comes with sodium as salt.
- Potassium: around 200 mg — a banana covers a session.
- Magnesium: around 10 mg — trivial.
- Calcium: around 20 mg — trivial.
Which reframes the whole electrolyte category: an "electrolyte supplement" is almost always a sodium supplement with four other minerals added for the label. A quarter to half a teaspoon of salt per litre of water is functionally equivalent to most commercial products, and cheaper — see electrolytes for the detail.
When you actually need it
Yes: sessions over about 90 minutes, hot or humid conditions, heavy sweaters, endurance events, two sessions in a day, and very low-carbohydrate diets (which increase sodium excretion — much of what is called "keto flu" is sodium depletion).
No: a 45–75 minute indoor lifting session, or daily use "for hydration" while eating a normal diet containing salt.
On the tension with public health advice: both things are true. Replacing what you sweat out is not the same as habitually eating a high-sodium diet, and the guidance to limit sodium exists for good cardiovascular reasons. If you have high blood pressure, that is a conversation for your doctor rather than a calculator.
Common questions
How much sodium do I need per day?
The general upper guideline is 2,300 mg. Sweat replacement is additional and depends on how much you actually sweat.
Do I need electrolyte drinks for a gym session?
Not for an hour indoors. Water is sufficient.
What is the best electrolyte drink?
For sweat replacement, salt in water — optionally with carbohydrate, since sodium and glucose are co-absorbed and speed fluid uptake.
Is coconut water good for electrolytes?
Not for sweat replacement. It is high in potassium and low in sodium, which is the wrong way round.
Related calculators
Track the numbers, not just calculate them
MyFitsy stores your weight, measurements and every session, so the figures above become a trend instead of a one-off.
