๐ CrCl Calculator 2026
Cockcroft-Gault Creatinine Clearance
Essential calculator for renal drug dosing adjustments
What is Creatinine Clearance (CrCl)?
๐ CrCl Explained
Creatinine Clearance (CrCl) estimates kidney function by measuring how efficiently creatinine is filtered from blood. The Cockcroft-Gault formula (1976) is the gold standard for drug dosing adjustments because most drug studies used this equation.
Unit: mL/min (milliliters per minute) โ Not normalized to body surface area like eGFR
๐ก For obese patients (>30% over IBW), adjusted body weight is automatically used.
๐ Creatinine Clearance Results
๐ Multiple Weight Calculations
| Weight Used | Weight (kg) | CrCl (mL/min) | Notes |
|---|
๐ Common Drug Dosing Thresholds
Cockcroft-Gault Formula
Standard Equation
Ideal Body Weight (IBW) โ Devine Formula
Adjusted Body Weight (AdjBW)
Body Surface Area (BSA) โ Du Bois
- Enter Patient Demographics: Age and sex are required for calculation.
- Enter Weight and Height: Needed to calculate IBW and determine weight adjustment.
- Check Weight Status: If >30% over IBW, adjusted weight will be used.
- Enter Serum Creatinine: From recent blood test (mg/dL or ฮผmol/L).
- Interpret for Drug Dosing: Match CrCl to drug-specific dosing recommendations.
Renal Function Categories
| Category | CrCl Range | Drug Dosing | Common Adjustments |
|---|---|---|---|
| Normal | โฅ90 mL/min | Full dose | No adjustment needed |
| Mild | 60-89 mL/min | Usually full dose | Some drugs require monitoring |
| Moderate | 30-59 mL/min | Dose reduction | 50-75% of normal dose common |
| Severe | 15-29 mL/min | Significant reduction | 25-50% of normal dose |
| ESRD/Dialysis | <15 mL/min | Special dosing | Post-dialysis dosing, avoid some drugs |
When to Use Different Weight Types
| Patient Type | Weight to Use | Rationale |
|---|---|---|
| Normal Weight (Within 30% of IBW) | Actual Body Weight | Standard approach for most patients |
| Obese (>30% over IBW) | Adjusted Body Weight | Fat tissue has minimal renal clearance contribution |
| Underweight ( Actual Body Weight | Using IBW would overestimate CrCl | |
| Fluid Overload | Dry Weight / IBW | Edema weight doesn't contribute to clearance |
| Amputees | Adjusted ABW | Add estimated limb weight correction |
Common Drug Dosing by CrCl
| Drug | Normal | CrCl 30-59 | CrCl 15-29 | CrCl <15 |
|---|---|---|---|---|
| Enoxaparin | 1 mg/kg q12h | 1 mg/kg q12h | 1 mg/kg q24h | Consider UFH |
| Gabapentin | 300-1200 mg TID | 200-700 mg BID | 100-300 mg daily | 100-300 mg post-HD |
| Metformin | Full dose | Use caution | Avoid | Contraindicated |
| Vancomycin | 15-20 mg/kg q12h | 15-20 mg/kg q24h | 15-20 mg/kg q48h | Levels-based |
| DOACs | Full dose | Reduced dose | Caution/Avoid | Avoid |
Official Resources
Frequently Asked Questions
CrCl = [(140 - Age) ร Weight] / (72 ร SCr), multiplied by 0.85 for females. Developed in 1976, it estimates creatinine clearance using age, weight, sex, and serum creatinine.
Drug dosing studies historically used Cockcroft-Gault. FDA drug labels specify CrCl (not eGFR) for dosing. Cockcroft-Gault is weight-based (mL/min), while CKD-EPI is BSA-normalized (mL/min/1.73mยฒ).
For patients >30% above IBW, use Adjusted Body Weight (AdjBW = IBW + 0.4 ร [ABW - IBW]). Fat tissue contributes minimally to creatinine clearance.
Controversial. Some clinicians round SCr to 0.8-1.0 mg/dL in elderly or cachectic patients to avoid overestimating CrCl. This is not universally recommended but may be prudent for nephrotoxic drugs.
CrCl (mL/min) = absolute clearance for individual patient. eGFR (mL/min/1.73mยฒ) = normalized to standard body surface area. For drug dosing, use CrCl. For CKD staging, use eGFR.
Devine formula: Males: 50 + 2.3 ร (height in inches - 60). Females: 45.5 + 2.3 ร (height in inches - 60). Or use kg: Males: 50 + 0.91 ร (height cm - 152.4).
Women have less muscle mass per kg of body weight compared to men. Since creatinine is produced by muscle, women generate less creatinine, hence the 0.85 correction factor.
No. Cockcroft-Gault assumes steady-state creatinine. In acute kidney injury (rising/falling creatinine), CrCl estimation is unreliable. Use clinical judgment and close monitoring.
Recalculate when creatinine changes significantly, weight changes >10%, or when starting/adjusting renally-cleared drugs. In hospitalized patients, often daily during acute illness.
No. Cockcroft-Gault was developed for adults. For children, use the Schwartz equation or Bedside Schwartz (height-based). Pediatric renal function develops with age.
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Last Updated: January 2026
