Renal function
Enter age, sex, serum creatinine, and the weight required by the dosing reference. Use the weight helper only when you need to compare common weight methods.
Cockcroft-Gault equation factor
This is a historical binary equation coefficient, not a gender-identity determination. Cockcroft-Gault has no universally validated factor-selection rule for transgender, nonbinary or intersex people. If you use the weight helper, the same selection also supplies the sex-specific Devine IBW constant.
Creatinine unit
Weight unit
Use the body weight specified by the medicine reference or local protocol. MedMaths converts lb to kg before applying Cockcroft-Gault.
Adult educational calculator. Confirm the requested renal estimate, creatinine unit, weight method, renal trend, and medicine-specific guidance independently.
Simple answer
Cockcroft-Gault estimates adult creatinine clearance from age, selected weight, the equation sex factor, and serum creatinine. Use the equation that matches the creatinine unit.
Serum creatinine in µmol/L
Serum creatinine in mg/dL
Historical equation factor: male = 1.0; female = 0.85. The original derivation used adult males and estimated the 15% female reduction rather than deriving a separate female model. Selected weight means the body-weight method required by the relevant medicine or clinical reference. The calculator does not decide whether actual, Devine ideal, adjusted, or another protocol-specified weight is clinically appropriate.
This calculator estimates adult creatinine clearance in mL/min from age, serum creatinine, the Cockcroft-Gault sex factor, and an explicitly selected weight. It is an estimate, not a measured clearance, diagnosis, CKD stage, or medication dose.
The National Kidney Foundation now advocates moving adult medication-related decisions toward race-free eGFR, with BSA adjustment when appropriate. FDA 2024 guidance prefers eGFR over eCrCl in renal-impairment pharmacokinetic studies. Some labels and protocols still specifically require Cockcroft-Gault CrCl, so use this page when that method is explicitly required and use the eGFR calculator for the CKD-EPI pathway.
Modern renal estimate
Use CKD-EPI 2021 eGFR for the modern race-free estimate. That calculator also supports the 2021 creatinine-cystatin C equation and optional BSA de-indexing.
Clinical use and safety
The arithmetic can be correct while the clinical decision is still wrong. These boundaries show what the calculator can and cannot establish.
Formula logic and known-value examples are checked as part of the MedMaths review process.
See how MedMaths checks calculator methods →Review the Cockcroft-Gault equations, worked examples, calculator limitations and common input checks.
Cockcroft-Gault subtracts age from 140, multiplies by the selected weight and sex factor, then divides by a serum-creatinine denominator. The denominator changes with the creatinine unit.
In simple words
Subtract age from 140. Multiply by the selected weight in kilograms and the sex factor. Divide by 0.814 multiplied by serum creatinine in micromoles per litre.
In simple words
Subtract age from 140. Multiply by the selected weight in kilograms and the sex factor. Divide by 72 multiplied by serum creatinine in milligrams per decilitre.
The mg/dL equation uses 72 in the denominator. The equivalent µmol/L equation uses 0.814 after unit conversion. A value in µmol/L must never be entered into the mg/dL equation.
Published equation provenance
Donald W. Cockcroft and M. Henry Gault published the original equation in 1976. For the derivation, weight-method discussion and limitations, read the Cockcroft-Gault Guide.
This calculator can show actual, Devine ideal and 0.4-adjusted weight values, but it does not decide which weight is clinically appropriate. Use the method required by the current source. For the broader actual-vs-IBW-vs-AdjBW comparison, read Ideal vs adjusted body weight for medication dosing; for Cockcroft-Gault-specific derivation and limitations, use the Cockcroft-Gault Guide.
Age 70 years, weight 80 kg, male factor 1.0, serum creatinine 120 µmol/L.
Age 65 years, weight 70 kg, female factor 0.85, serum creatinine 1.2 mg/dL.
It is an estimated creatinine clearance in mL/min calculated from age, selected weight, serum creatinine, and the Cockcroft-Gault sex factor.
A result of 57.3 mL/min is the calculator estimate produced from the entered values and selected weight method.
It uses the adult Cockcroft-Gault equation and reports estimated creatinine clearance in mL/min.
70 years, 80 kg, male, SCr 120 µmol/L → about 57.3 mL/min.
Use the unit shown on the pathology result. The calculator supports both units and changes the equation automatically.
106 µmol/L is approximately 1.20 mg/dL, not 106 mg/dL.
No. It calculates arithmetic only and does not select a medicine, dose, interval, threshold, or dialysis adjustment.
Be cautious when serum creatinine is changing rapidly or when creatinine does not reliably reflect filtration.
They may use different creatinine units, weight methods, rounding rules, height formulas, or automatic assumptions.
Recent kidney and pharmacy guidance increasingly supports race-free CKD-EPI 2021 eGFR, commonly BSA-adjusted when appropriate, for medication-related decisions. Cockcroft-Gault remains necessary when a medicine label, dosing reference, specialty protocol or exam specifically requires CrCl. Follow the named method rather than assuming either estimate universally replaces the other.
If the current source names eGFR or CKD-EPI 2021 instead of Cockcroft-Gault, use the eGFR Calculator.
Continue calculating
Use these calculators when a renal workflow requires a different kidney-function estimate, dosing weight, or body-size calculation.
Calculate the modern race-free 2021 CKD-EPI eGFR, with optional cystatin C and BSA adjustment.
Open calculatorCalculate adult Devine ideal body weight in cm or feet and inches, with optional Robinson and Miller comparison estimates.
Open calculatorCalculate body surface area from metric or imperial height and weight using four published formulas.
Open calculatorCalculate mg/kg per-dose or per-day orders using kg or lb, divided doses, and liquid concentration.
Open calculatorCalculate how many tablets are needed from fixed doses or mg/kg per-dose and per-day orders, with mcg/mg/g unit matching.
Open calculatorCalculate the commonly used simplified albumin-adjusted calcium estimate with current evidence limitations.
Open calculatorCalculate Devine + 0.4 adjusted body weight (AdjBW), with actual weight shown as a percentage of IBW for source-specific threshold comparison.
Open calculatorOpen the original Cockcroft-Gault publication and current renal-dosing guidance used for clinical context.
Cockcroft DW, Gault MH — Prediction of creatinine clearance from serum creatinine. Original 1976 publication of the Cockcroft-Gault equation.
National Kidney Foundation — Transition to Race-Free eGFR in Medication Decision-Making (2026). Multi-organisation guidance supporting race-free CKD-EPI 2021 eGFR, with BSA adjustment when appropriate, for medication-related decisions.
UK MHRA — Prescribing medicines in renal impairment. Guidance that eGFR is appropriate for most medicines while Cockcroft-Gault remains specifically required in selected medication and patient scenarios.
RCPA Manual — Creatinine clearance estimated: eGFR. Australian pathology guidance noting Cockcroft-Gault use for assisting drug-dosing decisions in renal impairment.
eviQ — Creatinine Clearance Calculator. Cockcroft-Gault formula, practice points, limitations, and oncology context.
NIDDK — Determining Drug Dosing in Adults with Chronic Kidney Disease. Guidance on matching kidney-function estimates to medicine-specific dosing information and recognising limitations of serum-creatinine equations.
U.S. FDA — Pharmacokinetics in Patients with Impaired Renal Function. Current guidance on estimating renal function for pharmacokinetic studies, including eGFR, Cockcroft-Gault eCrCl and body-weight considerations.
