Estimates creatinine clearance with the Cockcroft-Gault equation — the formula most often used to adjust medicine doses for kidney function.
For adults 18 and over. This is an estimate from a formula, not a measured clearance; it can mislead when muscle mass is very high or low, in pregnancy, or when kidney function is changing quickly. Medicine doses should always follow the official labeling and your prescriber's judgment.
How is creatinine clearance different from eGFR?
Both estimate kidney function from the same creatinine blood test. eGFR is adjusted for body surface area and is used mainly to stage kidney disease. Creatinine clearance (Cockcroft-Gault) is not size-adjusted and is still widely used to set doses of medicines that are cleared by the kidneys.
Why does this calculator ask for weight?
The Cockcroft-Gault formula uses body weight as a stand-in for muscle mass, because creatinine comes from muscle. That is also its main weakness: in people with very high or very low muscle mass the estimate can be off, and clinicians may adjust or measure clearance directly.
What is a normal creatinine clearance?
Healthy younger adults are often around 90–130 mL/min, declining gradually with age. Drug dosing usually compares the result against the thresholds in the medicine's official labeling rather than a single 'normal' value.