Creatinine Clearance Calculator

What Is Creatinine Clearance?

Creatinine clearance estimates how much blood plasma the kidneys clear of creatinine each minute. It is commonly reported in mL/min and is often used when reviewing kidney function for medication dosing or renal risk.

This calculator uses the Cockcroft-Gault equation, which estimates CrCl from age, sex, weight, and serum creatinine. If your lab reports creatinine in a different unit, the Creatinine mg/dL to µmol/L Calculator and µmol/L to mg/dL Conversion Calculator can help you compare values.

Cockcroft-Gault Formula

The Cockcroft-Gault equation estimates creatinine clearance in mL/min using serum creatinine in mg/dL and weight in kilograms.

Male CrCl = ((140 - age) x weight kg) / (72 x serum creatinine mg/dL)

Female CrCl = male result x 0.85

If creatinine is entered in µmol/L, this calculator converts it to mg/dL first using the standard creatinine relationship: 1 mg/dL is approximately 88.4 µmol/L.

Step-by-Step Example

Suppose a 50-year-old male weighs 80 kg and has serum creatinine of 1.0 mg/dL.

Example ((140 - 50) x 80) / (72 x 1.0) = 100 mL/min

For a female patient with the same age, weight, and creatinine, multiply by 0.85. The estimated CrCl would be 85 mL/min.

Creatinine Clearance vs eGFR

Creatinine clearance and eGFR are related but not identical. Cockcroft- Gault gives an absolute estimate in mL/min, while many eGFR equations report kidney function normalized to body surface area as mL/min/1.73 m2.

This distinction matters because many medication studies and drug dosing references historically used Cockcroft-Gault CrCl. Chronic kidney disease staging commonly uses eGFR instead, so always match the calculation to the clinical question.

Creatinine Clearance Interpretation

Creatinine clearance interpretation depends on the patient, the reason for testing, and whether kidney function is stable. The broad ranges below are educational only.

CrCl result	General interpretation
90 mL/min or higher	Often considered normal or near-normal kidney clearance in many adults.
60-89 mL/min	Mild reduction may be age-related or clinically relevant depending on context.
30-59 mL/min	Moderate reduction; commonly important for medication review.
15-29 mL/min	Severe reduction; medication dosing and nephrology context often matter.
Below 15 mL/min	Very low clearance; urgent clinical context may be needed.

Creatinine Clearance Quick Reference Chart

These examples use Cockcroft-Gault with the listed weight and serum creatinine values.

Age	Sex	Weight	Serum creatinine	Estimated CrCl
35	Male	80 kg	1.0 mg/dL	97 mL/min
50	Male	80 kg	1.0 mg/dL	100 mL/min
65	Female	65 kg	1.2 mg/dL	48 mL/min
78	Female	58 kg	2.0 mg/dL	22 mL/min
58	Male	72 kg	106 µmol/L	68 mL/min

Tips for Accurate Use

Use serum creatinine from a stable clinical state whenever possible. In acute kidney injury, creatinine may lag behind real-time kidney function, so Cockcroft-Gault can be misleading.

Weight choice can change the result substantially. Some medication protocols specify actual body weight, ideal body weight, or adjusted body weight. Follow the protocol or clinician guidance for the specific use case.

If you are reviewing acid-base or electrolyte results at the same time, the Anion Gap Calculator can help summarize sodium, chloride, and bicarbonate relationships.

Frequently Asked Questions

What equation does this creatinine clearance calculator use?

It uses the Cockcroft-Gault equation, which estimates creatinine clearance from age, sex, weight, and serum creatinine.

Can I enter creatinine in µmol/L?

Yes. Choose µmol/L in the creatinine unit selector. The calculator converts µmol/L to mg/dL before applying the Cockcroft-Gault formula.

Is creatinine clearance the same as eGFR?

No. Creatinine clearance from Cockcroft-Gault is an absolute estimate in mL/min. eGFR is usually indexed to body surface area and reported as mL/min/1.73 m2.

Why is sex included in the formula?

The original Cockcroft-Gault equation applies a 0.85 factor for female patients to account for average differences in muscle mass and creatinine generation.

Can this calculator be used for medication dosing?

It can support educational review, but medication dosing decisions should follow prescribing information, institutional protocols, and clinician or pharmacist judgment.

Calculate Creatinine Clearance