Urine Output Calculator

The urine output calculator helps to determine the urine output rate per kilogram weight of a person for every hour. In addition, the urine output calculator depends on the different variable factors. Moreover, the urine output calculator also estimates the fluid balance for the person based on fluid intake levels.

The urine output calculator provides different values for adult and pediatric patients. It helps to evaluate the urine output of any patient for every hour. There are some variables that help to estimate urine output. These are as follows:

  • Patients’ overall body weight
  • Daily fluid intake
  • Total urine output per day

What is the need for a urine output calculator?

A urine output calculator is a need of time. It provides greater information about the urine output per day. In addition, urine output calculators help to determine the health status of kidneys. It evaluates whether the kidneys are working properly or not. Moreover, the urine output calculator is an essential tool for physicians to understand any underlying kidney-related pathology.

There are several factors that are part of the urine output calculator. Some of the important factors are as follows:

Urine output

The urine output calculator provides information about kidney function in terms of blood filtration and waste excretion. Kidneys play a main role in excreting waste products in the form of urine. In this way, kidneys perform a function of urine production. Depending on the urine output, there are several conditions that indicate any disease process. Let us have a look to understand these conditions in a better way.


Polyuria is an increased and abnormal volume of urinary output. These are usually larger than normal values if not activated by more fluid intake. In addition, polyuria is an indication of diabetes insipidus, any kidney disease, or long-term use of diuretic drugs.


Oliguria is the opposite of polyuria. In this condition, the urinary output is lower than the normal values. Moreover, oliguria will indirectly affect the urinary output calculator. The main causes of oliguria are:

  • Renal diseases
  • Septicemic shock conditions
  • Drug intoxication
  • Myoglobin release

Acute oliguria

Acute oliguria indicates a severe level of oliguria. It dictates less than 400mL of urinary output per day. This phenomenon usually occurs due to rapid lowering in the glomerular filtration rate. In this way, urea and urine creatinine concentration in plasma increases. It causes acidosis and an increase in potassium concentration in plasma. Moreover, these conditions retain salt and water in the body. In this way, it decreases urinary output.

Acute oliguria falls into three categories. These are as follows:

  • Less than 0.5 mL/kg/hr for about six hours indicates a more risk of acute kidney injury.
  • Less than 0.5 mL/kg/hr for about twelve hours confirms the diagnosis of acute kidney injury disease.
  • Less than 0.3 mL/kg/hr for more than twenty-four hours or no urinary output for 12 hours indicates acute renal failure.

What is the normal urine output for every hour for adults and children?

There are different values of urine output for adults and children. Let us have a detailed look to understand the quantitative values of urine output.

For adults of more than 18 years of age

Urine output (mL/kg/hr):Explanation:
Lesser than 0.5Oliguria
Ranges from 0.5 to 5Normal healthy person
Greater than 5Polyuria

For children of lesser than 18 years of age

Urine output (mL/kg/hr)Explanation:
Lesser than 1Oliguria
Ranges from 1 to 3Normal healthy person
Greater than 3Polyuria

Why is there a need to calculate urine output?

Urine output is an important diagnostic test to confirm several diseases. In addition, urine output is also a factor in the urine output calculator to determine the rate. Moreover, urine output helps to evaluate creatinine, sodium, potassium, protein, and nitrogen levels. These are the indicators of various kidney diseases and pathologies. Urinary output is affected by various factors. These are as follows:

  • Any chronic kidney disease may affect the urinary output. Indirectly, it will also play a main role in affecting the urine output calculator.
  • Dehydration decreases urine output.
  • Certain drugs like diuretics
  • Caffeine intake may increase urinary output.
  • Drinking alcohol may also affect urinary output.
  • Fluid balance:

Fluid balance is also an important variable factor used in urine output calculators. It is the difference between normal fluid intake and total urine production.

Fluid balance = fluid intake – urine output

Normally, water loss must be equal to the water intake. Osmoregulation is the regulatory mechanism of human beings to maintain fluid balance in the body.

Water intake is in the form of drinking, eating, or any parenteral fluid intake. Water loss is usually in the forms of respiration, perspiration, expectoration, defecation, and urine. There may be several disturbances in fluid balance that may indicate any disease. In the case of dehydration, the value for fluid balance is usually negative. Fluid balance helps you to correct the fluid intake either by oral or intravenous routes.

A normal healthy person may exhibit symptoms of dehydration when he loses about 7% of the total water content of his body and 5% of his body weight.

How to use a urine output calculator to evaluate urine output rate?

To calculate the urine output rate, it is necessary to provide proper information to the urine output calculator. These are some of the requirements to put in the urine output calculator.

  • Patient age
  • Patient weight
  • Time period during which urine was collected
  • Urine output – it is the actual volume of urine collected over a specific time period
  • Patient’s fluid intake over a specific time period

These are the requirements to put in the urine output calculator to get your desired results. In addition, the urine output calculator will provide you with the urine output rate and fluid balance values.

In this way, the urine output calculator will also notify you when urine output decreases than the normal values, indicating acute kidney injury. Moreover, the urine output calculator also informs you about the oliguria or polyuria conditions.

How to practice a urine output calculator?

There is a need to practice a urine output calculator. It is better to be proficient in using a urine output calculator for better evaluation. Let us take an example for a better understanding of the urine output calculator.

  • Calculate the patient’s age, weight, urine output, and also the time period over which urine was taken.

For example:

Patient’s age = 20 years old
Patient’s weight = 60 kg
Urine output = 3000 mL
Time period = 24 hours

  • Use the following formula for urine output calculator to evaluate urine output rate.

Urine output (mL/kg/hr) = collected urine / weight × time

  • Weight should be in kilograms (kg).
  • Collected urine should be in milliliters (mL)
  • Time should be given in hours

Urine output (mL/kg /hr) = 3000 / 60 × 24
Urine output (mL/kg /hr) = 3000/1440
Urine output (mL/kg /hr) = 2.08 mL/kg/hr

  • Check from the normal range, If the value lies in the normal range.
  • As the value is equal to 2.08. This value range is normal for more than 18 years old.

Other calculators

There are several other calculators through which you can check your

  • Balanced daily water intake
  • Free water deficit
  • Bladder volume
  • Urine anion gap
  • Urine albumin to creatinine ratio
  • Kidney failure risk


The urine output calculator provides an accurate urine output rate to determine the kidney status. Urine production is solely the function of the kidney. An increase or decrease in the urine output rate helps to evaluate different diseases of the kidney. There are several conditions like oliguria and polyuria that are associated with several diseases.

Oliguria condition tells us about the decreased filtration of blood by the kidney. In this way, there is a decrease in urine output. Polyuria is a condition usually associated with diabetes insipidus.

Therefore, this urine output calculator helps you to provide an accurate urine output rate to assess your kidney’s condition. In addition, the urine output calculator also provides information about fluid balance to maintain a check and balance on the body’s condition. Moreover, the urine output calculator is a beneficial tool for physicians to understand any disease process of the kidney.

Frequently asked questions (FAQs)

What are the conditions that can cause oliguria?

There are several conditions that can cause oliguria. Oliguria is the reduction of urine output. These conditions include dehydration, infection, trauma, obstruction of the urinary tract, and several medications.

What are the factors that can affect urine output?

Urine output depends on several factors that can impact the rate of urine production. These are some of the factors.
● Using different types of food
● Amount of liquid consumption
● Amount of food consumption
● Fluid lost during breathing and perspiration
● Medical diseases
● Certain drugs

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