Creatinine Clearance Calculator

Calculate kidney function using the Cockcroft-Gault equation. Estimate CrCl for drug dosing adjustments.

years

Quick Reference

Normal CrCl
90+ mL/min
Healthy kidney function
Mild Decrease
60-89 mL/min
Stage 2 CKD
Moderate Decrease
30-59 mL/min
Stage 3 CKD
Severe Decrease
<30 mL/min
Stage 4-5 CKD

Your Results

Calculated
Creatinine Clearance
0 mL/min
Cockcroft-Gault
Weight Used
0 kg
Actual body weight
Creatinine
0 mg/dL
Serum level
CKD Stage 1
Normal or high kidney function
Clinical Note: Most medications can be dosed normally.

Understanding Creatinine Clearance

Creatinine clearance (CrCl) is a measure of how well the kidneys filter creatinine from the blood. It serves as an estimate of glomerular filtration rate (GFR) and is widely used for adjusting medication doses in patients with impaired kidney function.

The Cockcroft-Gault Equation

This calculator uses the Cockcroft-Gault equation, published in 1976:

CrCl (mL/min) = [(140 - age) x weight (kg)] / [72 x serum creatinine (mg/dL)]

For females: Multiply result by 0.85

The equation accounts for the fact that creatinine production decreases with age and is lower in females due to less muscle mass.

CKD Stages Based on GFR

StageGFR (mL/min/1.73m2)Description
190 or higherNormal kidney function
260-89Mildly decreased
3a45-59Mild to moderate decrease
3b30-44Moderate to severe decrease
415-29Severely decreased
5Less than 15Kidney failure

Clinical Applications

Drug Dosing

Many medications are primarily eliminated by the kidneys and require dose adjustments in renal impairment. Examples include:

  • Antibiotics (aminoglycosides, vancomycin, fluoroquinolones)
  • Anticoagulants (enoxaparin, dabigatran)
  • Diabetes medications (metformin, gliclazide)
  • Cardiac medications (digoxin, ACE inhibitors)
  • Pain medications (gabapentin, pregabalin)

Contrast Administration

CrCl is assessed before administering iodinated contrast media to evaluate the risk of contrast-induced nephropathy.

Limitations

  • Less accurate in extremes of body weight (obese or malnourished)
  • Not validated in acute kidney injury
  • May overestimate GFR in elderly patients
  • Affected by muscle mass variations
  • Some medications interfere with creatinine measurement

Weight Considerations

In obese patients, some clinicians recommend using:

  • Actual body weight for drug dosing (most common)
  • Ideal body weight to avoid overestimation
  • Adjusted body weight as a compromise

Medical Disclaimer

This calculator is provided for educational and informational purposes only. It should not be used as a substitute for clinical judgment or professional medical advice. Drug dosing decisions should be made by qualified healthcare professionals considering the complete clinical picture. The Cockcroft-Gault equation has limitations and may not be appropriate for all patients.