Weight change
0.5 kg lostThe calculation treats this as roughly 0.5 liters of fluid.
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Sweat rate calculator
Estimate how much fluid you lost during a workout.
How the calculation works
Weight lost in kilograms + drinks in liters − urine in liters = estimated sweat loss. Divide by workout hours to get liters per hour.
This measures one workout, not how much you should drink. Heat, clothing and exercise intensity affect the result. Avoid drinking enough to finish heavier than you started. Methods and sources.
A worked workout example
Imagine a 60-minute workout: 70 kg before, 69.5 kg after, 500 mL drunk and no urine passed.
Add what you drank
About 1 liter per hourAdd the 0.5 liters you drank to the estimated 0.5 liters lost from body weight, then divide by one hour.
This describes one workout; it is not a drinking target. Clothing, measurement errors and conditions can affect the estimate. Use the same scale and similar dry clothing for both measurements.
Read the fluid-loss method