However, a simple equation to help adults figure their fluid needs is that for every pound of body weight, you need about half an ounce of fluid intake per day. For instance, if you weigh lbs., simply multiply by.5 to estimate your daily fluid needs in ounces, then divide by eight to estimate your fluid needs in cups per day, rounding up to the nearest . Estimating energy, protein & fluid requirements. for adult clinical conditions. Requirements of Adults on Haemodialysis and Peritoneal Dialysis. https. Normal daily fluid and electrolyte requirements: 25–30 ml/kg/d water 1 mmol/kg/day sodium, Algorithms for IV fluid therapy in adults *.