Estimate creatinine clearance (CrCl) using the Cockcroft-Gault equation. Enter age, weight, serum creatinine, and sex to assess kidney function and guide medication dosing.
Normal: 0.6-1.2 (male), 0.5-1.1 (female)
Standard equation used by doctors for CKD staging
eGFR
81.8 mL/min/1.73m²
CKD Stage
G2
Mildly decreased
Stage G2: Mildly decreased
GFR: 81.8 mL/min/1.73m²
Mild reduction
GFR 81.8 mL/min/1.73m²
Used for drug dose adjustments — weight-dependent
Recommended CrCl
86.9 mL/min
Adjusted body weight (overweight/obese)
BMI: 25.8 kg/m²
Actual (81.6 kg): 92.8 mL/min
Ideal (73.0 kg): 83.0 mL/min
Adjusted (76.5 kg): 86.9 mL/min
Educational reference only. Always verify with current prescribing information.
500-1000 mg BID
300-600 mg TID
1 mg/kg BID
15-20 mg/kg q8-12h
For educational purposes only. Does not replace clinical judgment.
Creatinine clearance is a measure of how well the kidneys filter creatinine, a waste product of muscle metabolism. It serves as a practical estimate of the glomerular filtration rate (GFR). The Cockcroft-Gault equation, published in 1976, remains one of the most commonly used formulas in clinical practice, particularly for adjusting medication doses in patients with renal impairment.
CrCl naturally declines with age. Approximate normal ranges (source: NCBI StatPearls):
| Age Range | Male (mL/min) | Female (mL/min) |
|---|---|---|
| 20–29 | 97–137 | 88–128 |
| 30–39 | 91–131 | 82–122 |
| 40–49 | 85–125 | 75–115 |
| 50–59 | 78–118 | 69–109 |
| 60–69 | 72–112 | 63–103 |
| 70+ | 66–106 | 56–96 |
Chronic kidney disease is classified into stages based on GFR (source: KDIGO Clinical Practice Guidelines):
| Stage | GFR (mL/min/1.73m²) | Description |
|---|---|---|
| G1 | ≥90 | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mild to moderate decrease |
| G3b | 30–44 | Moderate to severe decrease |
| G4 | 15–29 | Severely decreased |
| G5 | <15 | Kidney failure |
| Feature | CrCl (Cockcroft-Gault) | eGFR (CKD-EPI) |
|---|---|---|
| Primary use | Drug dosing | CKD staging & prognosis |
| Requires weight? | Yes | No |
| Body surface area adjusted? | No (absolute) | Yes (per 1.73 m²) |
| FDA drug labels reference | Most commonly | Increasingly |
Sources: MDCalc, National Kidney Foundation
This calculator is for educational purposes only and does not replace clinical judgment. Always consult a healthcare professional for medical decisions.
Creatinine clearance (CrCl) estimates how well your kidneys filter creatinine, a waste product from muscle metabolism. It is measured in mL/min and approximates the glomerular filtration rate (GFR), helping clinicians assess kidney function and adjust medication dosing.
The Cockcroft-Gault equation estimates CrCl using age, weight, serum creatinine, and sex: CrCl = [(140 - age) x weight (kg)] / [72 x serum creatinine (mg/dL)], multiplied by 0.85 for females. Published in 1976, it remains the most commonly referenced formula for drug dosing adjustments.
Normal CrCl is approximately 97-137 mL/min for males and 88-128 mL/min for females. CrCl naturally declines with age at a rate of roughly 6.5 mL/min per decade after age 20. Values below 60 mL/min sustained for 3+ months indicate chronic kidney disease.
CrCl (via Cockcroft-Gault) and eGFR (via CKD-EPI or MDRD) both estimate kidney function but use different formulas. CrCl overestimates GFR because tubular secretion adds to creatinine clearance. Many drug dosing guidelines specifically reference Cockcroft-Gault CrCl, while CKD staging guidelines use CKD-EPI eGFR.
Many medications are cleared by the kidneys. When kidney function declines, drugs can accumulate to toxic levels. CrCl helps determine appropriate doses for renally excreted drugs such as vancomycin, aminoglycosides, enoxaparin, and metformin. The FDA often references Cockcroft-Gault in prescribing information.
CKD is staged by GFR: Stage G1 (≥90 mL/min, normal), G2 (60-89, mildly decreased), G3a (45-59, mild to moderate), G3b (30-44, moderate to severe), G4 (15-29, severely decreased), and G5 (<15, kidney failure requiring dialysis or transplant). Staging follows KDIGO 2024 guidelines.
The Cockcroft-Gault equation has limitations. It was developed in 1976 in a population of 249 men. It is less accurate in obese patients, elderly, critically ill, those with rapidly changing kidney function, amputees, and patients with very low muscle mass. It has not been validated in children.
For patients near their ideal body weight (BMI 18.5-25), use actual body weight. For obese patients (BMI >30), many pharmacists use adjusted body weight [IBW + 0.4 x (actual - IBW)] to avoid overestimating CrCl. For underweight patients, actual weight may underestimate true function.
Most FDA-approved drug labeling references Cockcroft-Gault for dose adjustments. Although the CKD-EPI equation is more accurate for CKD staging and prognosis, switching drug dosing guidelines would require extensive revalidation. Clinicians therefore continue to use Cockcroft-Gault for pharmacokinetic purposes.
Weight-Based Dosage Calculator
Calculate the correct medication dosage based on patient weight. Enter the ordered dose per kilogram, patient weight, and drug concentration to determine the total dose and volume to administer.
Body Surface Area Calculator
Calculate body surface area (BSA) using both the Mosteller and Du Bois formulas. Supports metric and imperial units for height and weight inputs.