Not for clinical use. This calculator supports clinical decisions (dosing, a risk score, an obstetric or laboratory assessment) and has not been reviewed by a named qualified clinician. It is published for reference and education only, it is excluded from search indexing for that reason, and it must not be used to guide the care of any patient. Verify every figure against the primary source and your own professional judgement.
Creatinine Clearance (Cockcroft-Gault) Calculator
The Cockcroft-Gault equation estimates creatinine clearance (CrCl) in mL/min, a measure of kidney filtration function widely used for renal dose adjustments in clinical practice. Published in 1976, it remains the most commonly referenced equation in drug package inserts. Enter the patient's age in years, weight in kilograms, serum creatinine in mg/dL, and biological sex. The calculator applies the formula CrCl = ((140 - age) x weight x sex factor) / (72 x serum creatinine), where the sex factor is 1.00 for males and 0.85 for females. This tool is for educational and reference use only; clinical decisions require professional judgment and consideration of patient-specific factors.
Cockcroft-Gault formula
CrCl = ((140 - age) x weight x sex factor) / (72 x SCr)
Sex factor: Male = 1.00, Female = 0.85
Age is in years, weight in kg, serum creatinine (SCr) in mg/dL, and CrCl result is in mL/min. The female multiplier of 0.85 accounts for lower average muscle mass and creatinine production compared to males.
Interpreting creatinine clearance
These bands describe the estimated clearance value itself. They are not chronic kidney disease stages: CKD staging is defined on eGFR from the CKD-EPI equation together with evidence of kidney damage persisting for at least three months, so it cannot be established from a single Cockcroft-Gault estimate. Cockcroft-Gault's validated use is renal drug dose adjustment, and many drug labels still specify it for that purpose.
- Above 90 mL/min: normal or high estimated clearance.
- 60-89 mL/min: mildly reduced. Most medicines need no adjustment at this level.
- 30-59 mL/min: moderately reduced. Many renally cleared drugs require dose reduction.
- 15-29 mL/min: severely reduced. Significant dose adjustment, and some drugs are contraindicated.
- Below 15 mL/min: kidney failure range. Dosing depends on whether the person is on dialysis.
Use the dosing guidance in the individual drug's approved label rather than inferring a dose from the band alone.
Frequently asked questions
What is the Cockcroft-Gault equation?
The Cockcroft-Gault equation estimates creatinine clearance (CrCl) as a proxy for glomerular filtration rate. The formula is CrCl = ((140 - age) x weight x 0.85 if female) / (72 x serum creatinine). Weight is in kilograms, serum creatinine in mg/dL, and the result is in mL/min.
Why is the female multiplier 0.85?
Women generally have less muscle mass than men of the same weight, producing less creatinine per unit of kidney function. Multiplying by 0.85 corrects for this difference, giving a more accurate estimate of kidney function.
Which weight should I use: actual, ideal, or adjusted?
Current practice recommends using actual body weight for patients at or below ideal body weight. For obese patients, adjusted body weight (IBW + 0.4 x (actual - IBW)) is often preferred to avoid overestimating CrCl. Clinicians should apply institutional guidelines.
Can this calculator tell me my chronic kidney disease stage?
No. CKD staging is defined on eGFR from the CKD-EPI equation together with evidence of kidney damage persisting for at least three months, so it cannot be established from a single Cockcroft-Gault creatinine clearance estimate. The bands shown here describe the estimated clearance value itself and are intended for renal drug dose adjustment, which is what Cockcroft-Gault is validated for. Staging is a clinical diagnosis for a doctor to make.
How is Cockcroft-Gault used in drug dosing?
Many drug package inserts still reference Cockcroft-Gault CrCl for renal dose adjustments, particularly for renally cleared medications such as digoxin, vancomycin, and many antibiotics. Pharmacists use CrCl to determine appropriate doses and dosing intervals.
Official sources
- National Kidney Foundation: GFR Calculator and CKD Guidance.
- NIH National Institute of Diabetes and Digestive and Kidney Diseases: CKD Tests and Diagnosis.
- FDA Drug Labeling Resources: FDA Drugs.
This content is provided for educational purposes only and has not been reviewed by a qualified specialist in this field. See our methodology and review panel.