The normal range for 24-hour urine volume is 800 to 2000 milliliters per day (with a normal fluid intake of about 2 liters per day). Oliguria is urine output < 500 mL in 24 h (0.5 mL/kg/h) in an adult. Oliguria is urine output < 1 L in 24 h (1 mL/kg/h) in a child.