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Sweat Rate and Fluid Replacement Calculator

mL/h sweat loss and hourly hydration target.

Calculates sweat rate = (pre_weight − post_weight + fluid_consumed) / exercise_hours. Recommends fluid replacement per hour to prevent >2% body mass deficit.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

kg
kg
L
h

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Sweat rate = (ΔBW + fluid_in) / time; replacement = sweat_rate × time

In depth

Calculates sweat rate = (pre_weight − post_weight + fluid_consumed) / exercise_hours. Recommends fluid replacement per hour to prevent >2% body mass deficit.