Hydration & Sweat-Rate Calculator

Your daily fluid target, and how much to replace after training

Good hydration is one of the easiest wins in nutrition. Use the daily target for everyday life, or the sweat-rate test to work out exactly how much you lose in a session and how much to drink back. These are general estimates, not personalised or medical advice.

Weight (kg)

Training today

Aim for around

— to — litres today

Little and often through the day. Warm weather, illness and altitude push this higher. Check your urine: pale straw means well hydrated, dark yellow means drink more.

Weigh yourself (minimal clothing) right before and right after a session, and note any fluid you drank during it.

Weight before (kg)

Weight after (kg)

Fluid drunk during (ml) leave 0 if none

Session length (minutes)

Please fill in your before and after weight and the session length.

Dial in your fuelling and hydration

A food diary analysis looks at the whole picture, including how you fuel and hydrate around training, and turns it into a plan for your sport.

Start your food diary analysis Book a free call

This calculator provides general nutritional guidance for education only. It is not medical advice, diagnosis or treatment, and it does not replace advice from your GP or a registered dietitian. Do not over-drink plain water during long events, as this can cause low blood sodium (hyponatraemia). Not intended for under-18s or during pregnancy.