BUN Calculator (Blood Urea Nitrogen)
Use this bun calculadora to estimate BUN, convert urea values, and compute the BUN/creatinine ratio.
What is BUN and why does it matter?
BUN stands for Blood Urea Nitrogen. It is a lab measurement that reflects how much nitrogen from urea is circulating in your bloodstream. Urea is produced in the liver when your body breaks down protein, and your kidneys are responsible for removing it. Because of this, BUN is commonly reviewed as part of kidney function testing.
A bun calculadora is useful when you want to quickly estimate or interpret values, especially if you have urea and creatinine numbers from a report and want to understand the relationship between them.
What this bun calculadora does
This tool helps you with three practical tasks:
- Direct BUN review: Enter BUN in mg/dL and get a quick range interpretation.
- Urea to BUN conversion: If your report lists urea (instead of BUN), the calculator can estimate BUN.
- BUN/Creatinine ratio: If creatinine is included, the calculator computes the ratio and shows a general interpretation range.
Formulas used
- BUN from urea (mg/dL): BUN = Urea × 0.467
- BUN from urea (mmol/L): BUN = Urea × 2.8
- BUN/Creatinine ratio: Ratio = BUN ÷ Creatinine
How to use the calculator correctly
Step-by-step
- Enter your BUN value if your lab report already provides it.
- If BUN is not available, enter your urea value and select the correct unit.
- Optionally enter creatinine to calculate the BUN/creatinine ratio.
- Click Calculate to see your results and interpretation.
Tip: Always make sure units match the ones shown in your lab report. Unit mix-ups are one of the most common reasons for confusion.
General interpretation guide
BUN range (adult reference, commonly used)
- Low: below 7 mg/dL
- Typical reference range: about 7 to 20 mg/dL
- Mildly elevated: 20 to 30 mg/dL
- High: above 30 mg/dL
BUN/Creatinine ratio
- Below 10:1: can be seen with low protein intake, liver issues, or overhydration in some contexts.
- 10:1 to 20:1: often considered a typical range.
- Above 20:1: may suggest dehydration or reduced kidney blood flow, among other possibilities.
These are broad clinical ranges and not a diagnosis by themselves. Doctors interpret BUN with other data such as eGFR, electrolytes, urine tests, medications, and symptoms.
Common factors that can change BUN
Reasons BUN may increase
- Dehydration
- High protein intake
- Kidney impairment
- Gastrointestinal bleeding
- Certain medications (for example, some steroids)
Reasons BUN may decrease
- Low protein intake or malnutrition
- Severe liver dysfunction
- Pregnancy (in some cases)
- Fluid overload
Frequently asked questions
Is a high BUN always a kidney problem?
No. Dehydration, diet, bleeding in the GI tract, and medications can raise BUN even when kidney disease is not the primary cause.
Can I rely on ratio alone?
Not entirely. The BUN/creatinine ratio is a useful clue, but clinical decisions should include full lab context and medical history.
Should I repeat testing?
If a value is borderline or unexpected, repeat testing and trend analysis are often more informative than a single isolated result.
Final note
This bun calculadora is designed for education and quick estimation. It can help you understand your numbers, prepare questions for your clinician, and reduce confusion around unit conversions. For treatment decisions, diagnosis, or urgent symptoms, always consult a licensed healthcare professional.
Medical disclaimer: This page is informational only and does not provide medical advice, diagnosis, or treatment.