Free tool

Fuel and sweat planner

Race-day carbohydrate, fluid and sodium in grams and litres, from the published guidelines and your own numbers. It runs in your browser: nothing you type is sent anywhere, and it's only kept on this device if you tick the box.

Race

Target time (h:mm:ss)

Body mass (kg)

Race-day temperature (°C, if known)

Your gels

Mixing brands, say 2 Maurten and 1 Precision? Add each gel and how many. Leave "How many" blank and the planner works out the number for your carb target.

Sweat rate

Work it out from a weigh-inI know itNot sure

Weigh yourself just before and just after a training run of an hour or more, in conditions like race day, in the same minimal clothing, towelled dry, on the same scales.

Weight before (kg)

Weight after (kg)

Drank during (ml)

Gels taken

Run length (min)

Temperature on the run (°C)

Skip runs with a toilet stop: it throws the numbers out.

How salty is your sweat?

Estimate it (3 questions)I've had a sweat testSkip

White salt marks on your kit after training

Sweat stinging your eyes

So how much salt do you think you lose?

Remember my answers on this device

Sources

Every number above comes from these sources; see how we check them. The planner shows what the guidelines say for someone of your size and race: it isn't a substitute for advice from a registered dietitian.