Creatinine Clearance Calculator (Cockcroft-Gault)

Estimate CrCl for medication dosing when eGFR is unavailable or protocol requires it.

Written by

Sid A. Abdala Balal

RGN · Medical & Nursing Content Author

Medically reviewed by

Dr. Adam Sayedi

MD · Emergency & Acute Medicine

⚠️ Safety note: Renal dosing: CrCl estimates vary in accuracy — confirm renally adjusted doses with pharmacy; eGFR may be preferred per local guidance.

Understanding this tool

Why nurses use it

Cockcroft-Gault creatinine clearance is still referenced for some drug dosing labels even when eGFR is reported. Nurses use CrCl estimates to support pharmacy conversations about renally cleared medicines.

When to use it

Use when a medication guideline specifically references CrCl, or as a secondary check to eGFR. Not reliable in AKI, obesity, or extreme muscle mass without adjustment.

Calculate

How to use this calculator

Enter age, weight, sex, and serum creatinine.
Compare CrCl with the drug’s renal dosing table.
Confirm adjustments with pharmacy.

How the calculation works

CrCl = [(140 − age) × weight × (0.85 if female)] ÷ (72 × SCr). Weight should be appropriate per protocol (actual vs ideal).

CrCl = [(140 − age) × weight × (0.85 if female)] ÷ (72 × SCr)

Formula used by this tool — verify units before applying at the bedside.

Worked example

Female, 70 y, 70 kg, Cr 1.4: CrCl ≈ 43 mL/min.

Limitations & clinical notes

Overestimates GFR in obesity; use adjusted body weight if protocol specifies.
Not for AKI — creatinine may not be at steady state.

References

Key sources: Cockcroft & Gault 1976.

Disclaimer: This calculator is for educational and bedside double-check purposes only. It does not replace institutional protocols, prescriber orders, pharmacist verification, or clinical judgment. Always follow your local policies — especially for high-risk medications, infusions, pediatrics, and critical care. If the patient is acutely unwell, escalate immediately rather than relying on any calculator output.