This hydration calculator helps you accurately determine your individual sweat loss, fluid replacement, sweat rate, and electrolyte needs for each workout. You enter your pre-exercise body weight (without clothes or in dry clothes), your post-exercise weight (without clothes or after removing sweaty clothing), your fluid intake during exercise, and your total workout duration. The calculator works in both metric (kg, liters) and imperial (lbs, ounces) units, automatically estimating your total sweat loss, your sweat rate per hour, your recommended hydration per workout, and a suggested electrolyte replacement range (low and high end). Once completed, you can enter your email address to receive a copy of your personalized hydration and electrolyte calculations for easy reference and planning.