What is the Cockcroft-Gault formula?

CrCl (mL/min) = [(140 - Age) x Actual Body Weight (kg)] / (72 x Serum Creatinine (mg/dL)). For females, multiply the result by 0.85. This equation was derived in 1976 and remains widely used for drug dosing.

When should I use actual vs. ideal body weight?

Use actual body weight for normal and underweight patients. For obese patients, many guidelines recommend using ideal body weight (IBW) or adjusted body weight (AdjBW). This calculator uses actual body weight by default, consistent with the original derivation.

Is CrCl the same as GFR?

They are related but not identical. CrCl slightly overestimates GFR because tubular secretion adds to creatinine excretion. For clinical drug dosing, CrCl is the preferred metric. For CKD staging, eGFR from CKD-EPI is preferred.

What units does this calculator use?

Serum creatinine is entered in mg/dL (US standard). Weight can be entered in kg or lb — the calculator converts automatically. The result is in mL/min.

How do I interpret the result?

A CrCl above 90 mL/min is considered normal. Values 60-89 indicate mildly reduced function, 30-59 moderately reduced, 15-29 severely reduced, and below 15 is consistent with kidney failure. These mirror CKD stages G1-G5.

Is this tool a substitute for medical advice?

No. This tool is for educational and informational purposes only. All clinical decisions about kidney function and drug dosing should be made by a licensed healthcare professional reviewing the full clinical picture.

Creatinine Clearance (Cockcroft-Gault)

Estimate creatinine clearance (CrCl) from age, weight, sex, and serum creatinine using the Cockcroft-Gault equation.

Patient Parameters

Age (years)

Body Weight

Serum Creatinine (mg/dL)

Biological Sex

Male Female

For educational use only. Not a substitute for clinical judgment.

Fill in patient data and press Calculate.

Summary

The Cockcroft-Gault equation estimates creatinine clearance (CrCl) as a surrogate for glomerular filtration rate (GFR). It uses age, body weight, sex, and serum creatinine to calculate how well the kidneys are filtering waste from the blood. Clinicians use CrCl to detect kidney disease, adjust drug dosages, and track renal function over time.

How it works

Enter the patient's age in years, body weight in kilograms (or pounds), and serum creatinine level.
Select the patient's biological sex — the formula applies a 0.85 correction factor for females.
The calculator applies the formula: CrCl = [(140 - Age) x Weight] / (72 x Serum Creatinine).
For females the result is multiplied by 0.85 to account for lower muscle mass on average.
The result is displayed in mL/min along with an interpretation based on CKD staging thresholds.

Use cases

Estimating kidney function when ordering drug dosing for renally cleared medications.
Screening patients for chronic kidney disease (CKD) staging.
Monitoring renal function trends over serial lab draws.
Adjusting antibiotic, anticoagulant, and chemotherapy dosing.
Pre-operative renal risk assessment.
Determining whether a patient qualifies for contrast-enhanced imaging.
Educational use in pharmacology and nephrology courses.
Double-checking pharmacy calculations at the point of care.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu

Creatinine Clearance (Cockcroft-Gault)

Patient Parameters

Formula Breakdown

CKD Stage Reference

Summary

How it works

Use cases

Frequently Asked Questions

Creatinine Clearance (Cockcroft-Gault)

Use the Creatinine Clearance (Cockcroft-Gault)

Patient Parameters

Formula Breakdown

CKD Stage Reference

Summary

How it works

Use cases

Frequently Asked Questions