Endurance hydration
Electrolyte drink mix calculator.
Scoops of carbohydrate powder and grams of salt for a bottle at a chosen carbohydrate percentage and sodium concentration, with carbs and sodium per hour.
Inputs
Mix
Enter your bottle size.
How do I mix a sports drink with the right carbs and sodium?
Carbohydrate: grams = bottle volume in mL times the percentage divided by 100. The ISSN nutrient timing stand cites a 6 to 8% carbohydrate solution (6 to 8 g per 100 mL) as an effective way to replace fluid and sustain blood glucose. Divide by the carbohydrate on your powder's label to get scoops.
Sodium: the ISSN ultra-marathon stand notes that, to reduce the chance of hyponatraemia in ultra racing, electrolytes (mainly sodium) may be needed at concentrations greater than most commercial products provide, that is above 575 mg per litre. This tool counts the sodium already in your powder, and converts any shortfall to table salt. Sodium is 39.3% of sodium chloride by mass (22.99 divided by 58.44), so grams of salt = milligrams of sodium divided by 393.4. Iodized or flavoured salts differ slightly, and 1 g of salt is a small pinch, so weigh it.
Carbohydrate and sodium per hour are the concentrations times how much you drink. If you drink more or less, the per-hour numbers move with it. A high-sodium drink is not suitable for everyone, including people told to limit sodium.
Frequently asked questions
How much sodium should be in a sports drink?
The ISSN ultra-marathon stand says ultra racing drinks may need more than 575 mg of sodium per litre to reduce hyponatraemia risk, and that most commercial products contain less. Needs vary with your sweat sodium loss, so treat it as a reference point and speak to a sports dietitian.
How much salt is that?
Salt (sodium chloride) is 39.3% sodium, so 575 mg of sodium per litre is about 1.46 g of salt per litre.
What carbohydrate concentration should a sports drink be?
The ISSN nutrient timing stand cites a 6 to 8% solution, which is 6 to 8 g of carbohydrate per 100 mL. Above that the tool flags it as outside the cited range.
Can I count the drink toward my carbs per hour?
Yes. The tool shows grams of carbohydrate per hour from the drink so you can subtract it in the gels calculator.
Sources
Checked
- Kerksick et al., ISSN position stand: nutrient timing, J Int Soc Sports Nutr 2017
- Tiller et al., ISSN position stand: nutritional considerations for single-stage ultra-marathon training and racing, J Int Soc Sports Nutr 2019
Ranges are quoted from the sources above and are general research or position-statement figures. Gel, powder and drink contents, spare gels and stop intervals are your own inputs; defaults are placeholders. One kilogram of body mass is treated as one litre of fluid.
Scope
Education only, not medical or dietetic advice. Needs differ by person, event, heat and training, and the published ranges are general. Try any fuelling or hydration plan in training, not for the first time on race day. If you have a medical condition (including diabetes, kidney or heart disease or high blood pressure), are pregnant or breastfeeding, or are under 18, ask your doctor or a registered dietitian first. Stop and get medical help for confusion, vomiting, severe headache, fainting or swelling of the hands and feet during or after a long effort.