Creatinine Clearance (Cockcroft-Gault) Calculator

Estimate creatinine clearance and kidney function using the Cockcroft-Gault equation for drug dosing.

Age (years) (years)

Sex

Weight (kg) (kg)

Serum creatinine (mg/dL) (mg/dL)

Ideal body weight (kg, optional) (kg)

Used if obese; leave 0 to auto-calculate

Please check your inputs and try again.

Worked Examples

Example 1: 65yo male, 70kg, Cr=1.2

CrCl=(140-65)×70/(72×1.2)

Result: 60.5 mL/min

Standard renal dosing reduction may be needed

Example 2: 80yo female, 55kg, Cr=1.0

CrCl=(140-80)×55/(72×1.0)×0.85

Result: 39 mL/min

Significant renal impairment — dose adjust

Frequently Asked Questions

Cockcroft-Gault vs CKD-EPI?

Use Cockcroft-Gault for drug dosing (FDA-approved drugs were typically tested using CG). Use CKD-EPI for CKD staging and disease monitoring. The two equations give different results.

What weight to use in obese patients?

Use adjusted body weight (ABW): IBW + 0.4×(TBW−IBW). Using total body weight overestimates CrCl in obese patients, risking drug toxicity.