This calculator is undergoing validation. Cross-check all calculations against primary sources or your institutional reference before clinical use.

Creatinine Clearance Calculator

Estimated renal function for adult drug dose adjustment. Includes Cockcroft-Gault and CKD-EPI 2021 equations.

Used by most drug package inserts for dose adjustment recommendations.

Patient

Age (years)

Sex

MaleFemale

Weight

Height

Serum creatinine

mg/dL

Cockcroft-Gault methodology

IDMS-traceable SCr correction: Modern labs report IDMS-traceable creatinine. Cockcroft-Gault was developed pre-IDMS, so the conventional SCr used in the equation is derived as (SCr_IDMS × 1.065) + 0.067.
Bidirectional IBW: Body weight used is the lower of actual body weight or Devine IBW. Protects against overestimating renal function in obese patients and in underweight/elderly patients with reduced muscle mass.
No cap (standalone calculator): Calculated CrCl is reported as-is, with interpretive guidance at clinical extremes. Drug-dosing calculators (e.g., vancomycin) apply the same IDMS and IBW corrections but additionally cap CrCl at 120 mL/min for downstream dose calculations to protect against overdosing in patients with apparent supranormal clearance. CKD-EPI 2021 and MDRD do not require IDMS correction and are shown as published.

Enter patient details and click Calculate to estimate creatinine clearance.

References

Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.

Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med. 2021;385(19):1737-1749.

Levey AS, Coresh J, Greene T, et al. Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate. Ann Intern Med. 2006;145(4):247-254.

Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650-655.

Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098.

KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314.

Modern clinical labs report IDMS-traceable serum creatinine values. The Cockcroft-Gault equation was developed pre-IDMS, so the conventional SCr used in the equation is derived as SCr_conv = (SCr_IDMS × 1.065) + 0.067. Body weight defaults to the lower of actual or Devine IBW to protect against overestimation in both obese and underweight-elderly patients. Salazar DE, Corcoran GB. Predicting creatinine clearance and renal drug clearance in obese patients from estimated fat-free body mass. Am J Med. 1988;84(6):1053-1060.

This calculator is intended for use by licensed pharmacy and healthcare professionals as an aid in estimating renal function for adult patients (≥18 years). It is not validated for pediatric patients, pregnancy, acute kidney injury, dialysis-dependent patients, or patients at extremes of muscle mass. Estimating equations approximate kidney function and may not reflect true GFR in any specific patient. Clinical judgment, trended labs, and direct measurement should guide drug dosing decisions when accuracy is critical.