Total volume, patient weight, and the hours it covers, computed to mL/kg/hr with every step of the arithmetic shown so you can check it against your own.
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mL / kg / hr
Fill in all three boxes and the steps appear here.
The rate is total volume divided by weight in kilograms, divided by the number of hours the volume was collected over. Dividing by weight gives mL per kilogram; dividing that by hours turns it into a per hour rate, which is what mL/kg/hr means.
Pounds are converted first. One kilogram is about 2.2046 pounds, so pounds are divided by 2.2046 to get kilograms. The converted weight is rounded to one decimal place, the way a scale reads it, and the rest of the math uses that rounded weight. That is why the step is printed: the numbers on screen are the numbers being divided, with nothing hidden behind them.
The result is rounded to two decimal places. The steps above it are shown at the precision they were used, so you can retrace the whole thing on paper and land on the same answer.
About 0.5 mL/kg/hr is the figure most commonly cited as adequate adult urine output. It is a reference point in wide use, not a pass or fail line, and it is the same threshold the acute kidney injury staging criteria are built around.
The KDIGO criteria use it directly. In the KDIGO 2012 Clinical Practice Guideline for Acute Kidney Injury, stage 1 acute kidney injury by the urine output criterion is output under 0.5 mL/kg/hr for 6 to 12 hours. Stage 2 is under 0.5 mL/kg/hr for 12 hours or more, and stage 3 is under 0.3 mL/kg/hr for 24 hours or more, or anuria for 12 hours or more. Sustained output below 0.5 mL/kg/hr for six hours or longer is therefore where the stage 1 window opens.
Hitting a threshold is not the same as knowing what to do about it. When to call, what to chart, how often intake and output gets totalled, and every escalation trigger come from your facility's policy and the ordering provider. This page does the arithmetic and stops there.
Pediatric expectations are different and are not handled here. Expected output per kilogram changes with age, and infants and small children sit well above the adult figure. Nothing on this page is scaled for them, so do not use it for a pediatric patient.
It also does not interpret anything. There is no fluid guidance, no medication logic, and no suggested response to a low number. It divides three numbers you supply and shows the division.
Use the actual current weight your unit charts. Whether that is the daily weight, the admission weight, or a documented dry weight is set by unit policy, not by this page. An out of date weight in the box produces a confidently wrong rate, because weight is a divisor and every error in it lands straight in the result.
How the urine was collected changes how much the number can carry. An indwelling catheter with a graduated drainage bag gives a measured volume over a known window, while voided, incontinent, or hat-measured output is an estimate, and the rate is only ever as good as the volume that went into it.
Partial hours are fine. The hours box takes decimals, so a 90 minute window is 1.5 and a 45 minute window is 0.75.
You don't have to take our word for it. Every browser has a built-in panel that shows everything a page sends or receives over the internet. On a computer (this doesn't work on a phone):