Creatinine Clearance Calculator
Compute creatinine clearance using validated scientific equations. See step-by-step derivations, unit analysis, and reference values.
Formula
CrCl = [(140 - Age) x Weight] / (72 x SCr) x 0.85 (if female)
Where CrCl = Creatinine Clearance in mL/min, Age = patient age in years, Weight = actual body weight in kg, SCr = serum creatinine in mg/dL. The 0.85 correction for females accounts for lower muscle mass. This is the Cockcroft-Gault equation, widely used for drug dosing adjustments.
Frequently Asked Questions
What is creatinine clearance and why is it important?
Creatinine clearance (CrCl) is a measure of how well the kidneys filter creatinine, a waste product of muscle metabolism, from the blood. It serves as a surrogate marker for the glomerular filtration rate (GFR), which is the gold standard measure of kidney function. CrCl is critically important for drug dosing, as many medications are eliminated by the kidneys and require dose adjustments when kidney function is impaired. A normal CrCl is approximately 90-140 mL/min for men and 80-125 mL/min for women, declining naturally by about 1 mL/min per year after age 40.
What factors affect serum creatinine levels?
Serum creatinine is primarily affected by muscle mass, which is why levels differ between males and females. Normal ranges are 0.7-1.3 mg/dL for men and 0.6-1.1 mg/dL for women. High-protein diets, creatine supplements, and intense exercise can temporarily increase creatinine. Certain medications like trimethoprim and cimetidine can raise serum creatinine without affecting actual kidney function by blocking tubular secretion. Age-related muscle loss means that even a normal creatinine in an elderly patient may mask significant kidney impairment.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
How accurate are the results from Creatinine Clearance Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
Does Creatinine Clearance Calculator work offline?
Once the page is loaded, the calculation logic runs entirely in your browser. If you have already opened the page, most calculators will continue to work even if your internet connection is lost, since no server requests are needed for computation.
Can I share or bookmark my calculation?
You can bookmark the calculator page in your browser. Many calculators also display a shareable result summary you can copy. The page URL stays the same so returning to it will bring you back to the same tool.