Creatinine Clearance Calculator

Calculate creatinine clearance (CrCl) using Cockcroft-Gault for drug dosing. Includes 24-hour urine method, drug dosing guide for vancomycin and aminoglycosides, and obesity body weight adjustment.

yrs
kg
mg/dL
Creatinine Clearance (mL/min)
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Renal Dosing Category —
Extended More scenarios, charts & detailed breakdown ▾
yrs
kg
mg/dL
CrCl (mL/min)
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Dosing Category —
Professional Full parameters & maximum detail ▾
yrs
kg
cm
mg/dL
CrCl (mL/min)
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Ideal Body Weight —
Weight Used for CrCl —
Obesity Adjustment Note —
Vancomycin Interval —

How to Use This Calculator

  1. Enter age, weight (kg), serum creatinine (mg/dL), and sex.
  2. Results show CrCl in mL/min and a renal dosing category.
  3. Use 24-hour Urine tab for measured CrCl from a urine collection.
  4. Use Drug Dosing Guide for specific drug dosing thresholds.
  5. Use Professional for obesity-adjusted body weight calculations.

Formula

CrCl = ((140 - age) x weight x sex factor) / (72 x serum Cr)

Sex factor: 1.0 male, 0.85 female. 24-hr urine: CrCl = (Urine Cr x Volume) / (Serum Cr x 1440).

Example

Example: 65-year-old female, 60 kg, Cr = 1.1 mg/dL. CrCl = (140 - 65) x 60 x 0.85 / (72 x 1.1) = 3825 / 79.2 = 48.3 mL/min (moderate reduction).

Frequently Asked Questions

  • Creatinine clearance (CrCl) is used primarily for drug dosing in patients with reduced kidney function. Unlike eGFR, it is not BSA-normalized. FDA-approved drug labeling for renally cleared drugs like vancomycin, aminoglycosides, metformin, and anticoagulants specifies dosing based on CrCl.
  • Both estimate kidney function. eGFR (CKD-EPI) is normalized to 1.73 m2 BSA and is used for CKD staging. CrCl (Cockcroft-Gault) uses weight and is used for drug dosing. For most adults of average size, the values are similar, but they diverge in very large or very small patients.
  • In obese patients, using actual body weight overestimates CrCl. Standard guidance: use ideal body weight (IBW) or adjusted body weight (ABW = IBW + 0.4 x (Actual - IBW)) for patients with actual weight > 130% of IBW.
  • CrCl (mL/min) = (Urine Cr mg/dL x Urine Volume mL) / (Serum Cr mg/dL x 1440 min). The 24-hour urine method is the most accurate non-invasive measurement but requires precise urine collection over exactly 24 hours.
  • Metformin is contraindicated when CrCl < 30 mL/min due to risk of lactic acidosis. FDA advises dose reduction for CrCl 30-45 mL/min. Regular renal monitoring is recommended for all patients on metformin.

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Sources & References (5) ▾
  1. Cockcroft DW & Gault MH (1976) — Prediction of Creatinine Clearance from Serum Creatinine, Nephron — Nephron / Karger
  2. KDIGO 2024 — Drug Dosing in Chronic Kidney Disease — KDIGO
  3. NCBI StatPearls — Creatinine Clearance — NCBI / StatPearls
  4. Sanford Guide to Antimicrobial Therapy — Renal Dosing — Antimicrobial Therapy Inc.
  5. ASHP — Drug Prescribing in Renal Failure (Aronoff et al.) — American Society of Health-System Pharmacists