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BUN/Creatinine Ratio Calculator

BUN ÷ Cr ≈ 10–20 normally; > 20:1 suggests pre-renal AKI.

Compute the BUN/creatinine ratio from a basic metabolic panel. A ratio > 20:1 raises suspicion for pre-renal volume depletion, while < 10:1 suggests intrinsic renal disease or low protein intake.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

mg/dL
mg/dL

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

BUN / Cr ratio in (mg/dL) / (mg/dL).

In depth

Compute the BUN/creatinine ratio from a basic metabolic panel. A ratio > 20:1 raises suspicion for pre-renal volume depletion, while < 10:1 suggests intrinsic renal disease or low protein intake.