BUN to Creatinine Ratio Calculator

BUN and Creatinine Ratio Estimator

Input Fields

Blood Urea Nitrogen

mg/dL

Enter your BUN level in mg/dL

Serum Creatinine

mg/dL

Enter your serum creatinine level in mg/dL

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Calculate automaticallyIf enabled, the result will update automatically when you change any value.

Your Results

BUN to Creatinine Ratio (BUN:Cr)

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BUN to Creatinine Ratio Formula

$$\text{BUN to Creatinine Ratio} = \frac{\text{BUN (mg/dL)}}{\text{Creatinine (mg/dL)}}$$

Interpretation:

• Normal Range: 10:1 to 20:1
• 20:1 → May indicate prerenal causes (e.g., dehydration)
• <10:1 → May suggest intrinsic renal issues or liver disease

The BUN to Creatinine Ratio is commonly used in nephrology and emergency care to distinguish between prerenal, renal, and postrenal causes of kidney dysfunction. BUN (Blood Urea Nitrogen) levels can vary due to protein intake and hydration status, while creatinine is a more stable indicator of kidney filtration. A high or low ratio helps clinicians narrow down the potential causes of acute kidney damage or chronic kidney disease.