BUN/Creatinine Ratio Calculator

The BUN/creatinine ratio is a calculation comparing the amount of blood urea nitrogen (BUN) to serum creatinine in your blood. It is used clinically as a general indicator of kidney health and hydration status.

The ratio is calculated by dividing your blood urea nitrogen (BUN) value by your serum creatinine value. Both values are measured in milligrams per deciliter (mg/dL). Formula: Ratio = BUN ÷ Creatinine.

For most healthy adults, a normal or typical ratio is between 10:1 and 20:1. This indicates balanced kidney filtration, normal protein metabolism, and adequate hydration.

A ratio higher than 20:1 often points to pre-renal causes (factors outside the kidneys), most commonly dehydration, which causes BUN to rise faster than creatinine. Other causes include gastrointestinal bleeding (which increases protein breakdown), congestive heart failure, or a very high-protein diet.

A ratio lower than 10:1 may indicate intrinsic kidney damage (such as acute tubular necrosis, where the kidneys cannot filter waste), severe liver disease (which reduces urea production), malnutrition, a low-protein diet, SIADH, or pregnancy.

Yes. They are standard components of basic metabolic panels (BMP) and comprehensive metabolic panels (CMP) ordered during routine checkups or to monitor kidney function.

If the ratio is elevated due to dehydration, drinking more water will help normalize it. If it is caused by high protein intake or dietary supplements, adjusting your diet can help. If it is due to an underlying kidney or liver condition, treatment should be directed by your healthcare provider.

Not necessarily. A temporary elevation can simply mean you are mildly dehydrated or recently consumed a high-protein meal. However, a persistently high ratio, especially in combination with other symptoms or elevated individual markers, should be evaluated by a medical professional.