What is the typical adult minimum urine output per hour?

• A. About 60 mL per hour
• B. About 30 mL per hour
• C. About 5 mL per hour
• D. About 100 mL per hour

Answer: (B)

Urine output is a quick gauge of kidney perfusion and fluid status. The usual benchmark clinicians use is about 0.5 mL of urine per kilogram of body weight per hour, which for many adults translates to roughly 30 mL per hour. This minimum helps ensure the kidneys are receiving enough blood flow to filter fluids and waste; dropping below it can signal dehydration, low blood volume, or developing kidney injury, prompting closer assessment and management. A value around 60 mL per hour would indicate more than the minimum and is typically a sign of adequate or higher-than-minimum production, not the baseline expectation. A rate of about 5 mL per hour is far below the threshold and indicates severe oliguria, while 100 mL per hour is simply higher than the minimum and not the standard baseline to aim for.