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BUN Creatinine Ratio Calculator

BUN Creatinine Ratio Calculator


Normal BUN/Creatinine ratio = 10 : 1

BUN - Blood Urea Nitrogen


Serum Creatinine



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The BUN Creatinine Ratio Calculator measures the ratio of blood urea nitrogen to creatinine which is essential to diagnose the causes of acute renal failure.

What is Bun/Creatinine Ratio?

The BUN Creatinine Ratio is the key indicator of kidney functionality of the kidney. BUN(Blood Urea Nitrogen) and Creatinine are substances produced by metabolism. BUN(Blood Urea Nitrogen) is filtered by the nephrons of kidneys and it is reabsorbed in our blood constantly. Creatinine is mostly filtered away in our urine.
What is Bun/Creatinine Ratio?

Bun creatinine ratio calculation indicates the functionality of our kidneys. When our kidneys malfunction Bun creatinine ratio calculation is disturbed and normally goes higher. 

How is Urea Produced?

Urea is a liver waste product, it is produced when the body processes or digests protein. The Urea is filtered away by our kidneys and the rate of urea filtration can be measured by a protein creatinine ratio calculator. High urea content in our blood is an indicator of kidney dysfunction or Azotemia. 

How to Calculate BUN Creatinine Ratio?

You can calculate the BUN creatinine ratio by the blood test. Blood tests can reveal a lot about your metabolism, kidney, liver, and overall health. 

The formula for BUN Creatinine Ratio:

BUN/Creatinine Ratio =  Serum BUN/Creatinine

BUN Creatinine ratio calculation is measured in serum separated from the blood.US units and SI units are used to calculate BUN creatinine ratio, The reference normal bun and creatinine levels are given below:

Parameter US Units Range SI Units Range
Blood Urea Nitrogen (BUN) 7 – 30 mg/dL 2.5 – 10.7 mmol/L
Creatinine 0.7 – 1.2 mg/dL 62 – 106 µmol/L

Normal BUN and Creatinine Levels:

The normal bun and creatinine levels are given below:

  • BUN/Creatinine ratio = 10 :1
  • On normal diet = 12 to 16
  • Optimum adult level = 15.5

Normal bun and creatinine levels can be measured by the normal bun creatinine ratio calculator.

Causes of Bun creatinine ratio Disturbance:

The normal bun and creatinine levels can be disturbed due to various reasons like dehydration and malnutrition. The bun creatinine ratio calculation is due to the extraordinary intake of protein.

  • BUN/creatinine ratio >20 suggests a Prerenal cause
  • BUN/creatinine ratio <10 suggests an Intrinsic renal cause
BUN/Creatinine >20 BUN/Creatinine <10
Dehydration Malnutrition
Hypovolemia Pregnancy
High protein intake Acute tubular necrosis
Congestive heart failure SIADH (syndrome of inappropriate antidiuretic hormone)
Heart attack Rhabdomyolysis
Gastrointestinal bleeding

How to use the Bun Creatinine Ratio Calculator?

For accurate and precise Bun creatinine ratio calculation follow the instructions:


  • Enter the BUN – Blood Urea Nitrogen 
  • Serum Creatinine value
  • Then press the calculate


  • Bun to Creatinine Ratio 


From the source of BUN Creatinine Ratio, Disturbance causes

From the source of Blood Urea Nitrogen, Normal BUN/creatinine ratio