Creatinine Clearance Equation Calculator

Advanced creatinine clearance form

Calculation method

Age

Sex factor

Weight

Weight unit

Weight used in equation

Height

Height unit

Adjusted weight factor

Serum creatinine

Serum creatinine unit

Urine creatinine

Urine creatinine unit

Urine volume

Total volume in mL for the collection.

Collection time

Use 24 for a full day collection.

Formula used

The calculator supports estimated and measured clearance methods.

Cockcroft Gault equation

CrCl = ((140 − age) × weight in kg) ÷ (72 × serum creatinine in mg/dL)

For the female sex factor, multiply the result by 0.85.

Timed urine clearance equation

CrCl = (urine creatinine × urine flow rate) ÷ serum creatinine

Urine flow rate equals total urine volume divided by collection minutes.

Body size adjustment

BSA adjusted CrCl = CrCl × 1.73 ÷ BSA

BSA uses the Mosteller equation: square root of height in centimeters times weight in kilograms, divided by 3600.

How to use this calculator

Select Cockcroft Gault, timed urine clearance, or both.
Enter age, sex factor, weight, height, and serum creatinine.
Choose the correct units for weight, height, and creatinine.
Select actual, ideal, or adjusted body weight for the estimate.
Add urine values when using the timed collection method.
Press the calculate button and review the result above the form.
Use CSV or PDF export to save the calculation summary.

Example data table

Case	Inputs	Method	Approximate result
Adult male	55 years, 80 kg, SCr 1.2 mg/dL	Cockcroft Gault, actual weight	78.70 mL/min
Adult female	65 years, 65 kg, SCr 1.4 mg/dL	Cockcroft Gault, actual weight	41.11 mL/min
Urine collection	UCr 100 mg/dL, volume 1500 mL, SCr 1.1 mg/dL	24 hour urine clearance	94.70 mL/min

Creatinine Clearance Overview

Creatinine clearance estimates how quickly kidneys remove creatinine from blood. It is often used when medicine dosing needs renal adjustment. The value is not the same as eGFR. It is still useful because many drug labels reference Cockcroft Gault clearance.

Why This Estimate Matters

Creatinine comes from normal muscle activity. Healthy kidneys filter it into urine. When filtration falls, serum creatinine often rises. Clearance converts age, weight, sex, and serum creatinine into a practical flow rate. The result is shown in milliliters per minute. A lower value may suggest reduced renal elimination.

Cockcroft Gault Method

The Cockcroft Gault equation is common for adult dosing checks. It uses age, body weight, serum creatinine, and a sex factor. Weight choice matters. Actual weight can overstate clearance in obesity. Ideal weight may understate clearance in some larger patients. Adjusted weight is often used when actual weight is far above ideal weight.

Measured Urine Clearance

A timed urine collection can estimate clearance from urine creatinine, serum creatinine, collection volume, and time. This method depends on complete collection. Missed urine lowers the estimate. Extra collection time or wrong volume can also distort the result. Always review unusual values.

Body Surface Adjustment

Some reports normalize clearance to 1.73 square meters. This calculator can show a body surface adjusted value. The adjustment helps compare people of different body size. Drug dosing often uses the unadjusted value, so both numbers may be helpful.

Using Results Safely

Results should be checked with clinical context. Hydration, diet, pregnancy, muscle mass, amputation, and unstable kidney function can change creatinine behavior. Very high or very low body size can also reduce accuracy. This page gives calculation support only. It does not diagnose kidney disease. It does not replace professional judgment. Use it to prepare a clearer discussion with a qualified clinician.

Practical Tips

Enter recent lab values. Match every unit before calculating. Use the same serum creatinine source for each comparison. Save the CSV for records. Download the PDF when sharing a summary. Recalculate after major weight changes, new labs, or treatment changes. For urgent symptoms, seek care, especially with swelling, confusion, chest pain, or low urine output.

FAQs

What is creatinine clearance?

Creatinine clearance estimates how much blood plasma the kidneys clear of creatinine each minute. It can be estimated from an equation or measured with urine collection data.

Is creatinine clearance the same as eGFR?

No. Creatinine clearance and eGFR are related, but not identical. Many drug dosing references use Cockcroft Gault creatinine clearance rather than lab reported eGFR.

Which weight should I choose?

Actual weight is common. Ideal or adjusted weight may be useful when body size is far from average. Follow the method used by your clinical setting.

Why is sex used in the equation?

The Cockcroft Gault equation includes a female factor of 0.85. This accounts for average differences in muscle mass and creatinine production in the original equation.

Can I use µmol/L creatinine?

Yes. Select µmol/L in the serum creatinine unit field. The calculator converts it to mg/dL before applying the clearance equations.

What does BSA adjusted mean?

BSA adjusted clearance normalizes the result to 1.73 square meters. It helps compare people with different body sizes, but drug dosing may use unadjusted clearance.

Why does urine collection accuracy matter?

Timed urine clearance depends on complete volume collection and correct timing. Missing urine, extra time, or wrong volume can make the calculated result misleading.

Can this calculator diagnose kidney disease?

No. It provides calculation support only. Diagnosis needs clinical history, lab trends, urine testing, imaging when needed, and professional medical judgment.