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About this tool
Bottles per hour, refill stops, carbs and sodium for a ride, from your weight, duration, heat, humidity and riding intensity.
This calculator converts a planned ride into bottles per hour, refill stops, carbohydrate grams and drink sodium. It models sweat rate from rider weight, ride intensity, air temperature and humidity, then applies the ACSM Position Stand on Exercise and Fluid Replacement: drink at your sweat rate but no faster than the gut can absorb it (about 1 L per hour), finish under 2% body-mass loss, and replace 1.5 litres for every kilogram still down. Carbohydrate follows the duration bands in the ACSM joint position on Nutrition and Athletic Performance — roughly 30 g/h from one hour, 60 g/h from two, and up to 90 g/h past two and a half.
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Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Turns litres per hour into bottles per hour and the number of refill stops your cages force.
Gives carbohydrate grams per hour and drink sodium alongside the volume.
Caps intake at your sweat rate so the plan never pushes you toward over-drinking.
Match your sweat rate, which for most riders is 0.5-1.5 litres an hour and rises steeply with heat. Practically that is one 500-750 ml bottle an hour in mild weather and up to two in the heat, capped near 1 litre an hour because that is roughly what the gut can absorb while riding.
For a 3-4 hour ride at moderate temperature, plan on 3-4 large bottles — about 750 ml per hour. Two cages means at least one refill stop, so check where the taps or feed stations are before you set off.
About 30 g/h for rides of 1-2 hours, 60 g/h for 2-2.5 hours, and up to 90 g/h beyond that. The 90 g figure only works with a glucose-plus-fructose blend, because a single sugar saturates its intestinal transporter near 60 g per hour.
Yes. Drinking more than you sweat over several hours dilutes blood sodium and can cause exercise-associated hyponatraemia, which is more dangerous than mild dehydration. Never plan to drink faster than your sweat rate, and on rides over two hours use a drink containing roughly 460-690 mg of sodium per litre. This is general information, not medical advice.
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