Sweat Rate Calculator

Sweat Rate Calculator

Knowing your sweat rate lets you build a hydration plan that prevents both dehydration and overdrinking. Weigh yourself before and after a workout, note the fluid you drank and how long you trained, and this calculator works out total fluid loss, your sweat rate per hour, the dehydration as a percentage of body weight, and a suggested drinking rate. Sweat rate varies a lot with heat, intensity and the individual, so test it in conditions similar to your event.

Weigh yourself nude before and after, drying off first. Each 1 kg of weight lost ≈ 1 L of sweat. Aim to replace 100–150% of losses after exercise and to drink close to your sweat rate during long sessions; a fluid loss over 2% of body weight starts to impair performance.