Calculate hourly urine output from total urine volume and time, or find total volume or hours, with optional mL/kg/hr using body weight.

Average over the measured collection period. This calculation does not diagnose kidney function; very low/no output or concerning symptoms need prompt medical assessment.

Default: not saved; page reload clears it. With permission, other scripts on this site can access saved values. Reset removes them; expired data is removed on the next visit.

Body weight normalization

Blank omits mL/kg/h. Use the weight appropriate to the clinical measurement.

Medical note: This calculator is for informational purposes only and does not diagnose or treat any condition. Urine output interpretation depends on factors like age, body size, medications, and overall health. If you have very low or no urine output, signs of severe dehydration, confusion, chest pain, shortness of breath, severe weakness, or swelling, seek urgent medical care or contact a clinician promptly.

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Hourly Urine Output Formula

The following formula is used to calculate the hourly urine output for a given total urine output and number of hours.

U = T / H

Variables:

  • U is the hourly urine output (ml/hour)
  • T is the total urine output (ml)
  • H is the number of hours

To calculate the hourly urine output, divide the total urine output by the number of hours. In some settings, urine output is also tracked as mL/kg/hr (normalized to body weight): divide the average mL/hour by body weight in kilograms. This is an average over the entered collection interval and can conceal shorter periods of low or no output; it does not classify kidney function.

What is Hourly Urine Output?

Hourly urine output is a measure of the volume of urine produced by the kidneys per hour. It is an important parameter used in clinical monitoring of kidney function and fluid balance. It is typically measured in milliliters per hour (ml/hour).

How to Calculate Hourly Urine Output?

The following steps outline how to calculate the Hourly Urine Output.

  1. First, determine the total urine output (T) in milliliters.
  2. Next, determine the number of hours (H) over which the urine was collected.
  3. Finally, calculate the hourly urine output using the formula U = T / H.
  4. Choose the quantity to solve, enter the two required measurements and select Calculate. Body weight is optional. Saving health inputs is off by default; explicit permission allows browser restoration for 24 hours, with expired data removed on the next visit.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Total urine output (T) = 1200 ml

Number of hours (H) = 6 hours

Hourly urine output (U) = 1200 / 6 = 200 mL/hour (0.2 L/hour)