Creatinine Clearance (Cockcroft Gault Equation) Calculator

Use this Creatinine Clearance calculator to estimate CrCl in mL per minute with the Cockcroft Gault equation. Adjust for age, sex, body weight, and serum creatinine. This tool is built for USA and global clinicians who need a fast renal function estimate for drug dose and kidney safety checks.

Results are for adult patients only and for education. They do not replace clinical judgment, lab data, or local dosing guidelines.

Renal dosing tool · Creatinine Clearance Cockcroft Gault

Cockcroft Gault Inputs

Enter patient age, sex, weight, and serum creatinine. Choose units that match your lab report. The calculator uses the Cockcroft Gault equation and shows CrCl in mL per minute.

years
Cockcroft Gault is for adults. Use age in whole years.
The equation multiplies by 0.85 for females.
kg
Use actual body weight unless your protocol says otherwise.
The tool converts pounds to kilograms when needed.
cm
Height lets the tool show BSA and CrCl normalised to 1.73 m².
mg/dL
Use a stable creatinine value from the lab.
The equation works in mg/dL. The tool converts from µmol/L if needed.
For obesity some guides use adjusted weight. See notes below.
Education tool. Not a stand alone dosing guide.

Always confirm results with local lab ranges and your pharmacy team. Do not use this calculator for dialysis patients, children, pregnancy, or very unstable kidney function.

0 mL/min
Creatinine Clearance by Cockcroft Gault
CrCl (actual body size) 0 mL/min
CrCl normalised to 1.73 m² 0 mL/min/1.73 m²
Body surface area 0.00 m²
Weight used in equation 0.0 kg
Serum creatinine (mg/dL) 0.00
Sex factor 1.00
Age factor (140 - age) 0
Renal function band Not calculated
CrCl = (140 - age) × weight (kg) ÷ (72 × SCr) and × 0.85 if female
CrCl not yet calculated Weight type: actual SCr in mg/dL
This Creatinine Clearance calculator is a support tool only. It does not give medical advice or replace your renal dosing protocol, local drug guide, or pharmacist review.

What Is Creatinine Clearance

Creatinine Clearance, often written as CrCl, is a way to estimate how well the kidneys clear creatinine from the blood. It is used as a simple marker for kidney function. Many drug labels and dosing tables still use CrCl to set safe dose ranges for renally cleared drugs.

Creatinine is a small waste product from muscle. Healthy kidneys filter it into the urine. When kidney function drops, creatinine builds up in the blood and the measured serum creatinine rises. Creatinine Clearance is an estimate of that filtration rate in mL per minute.

In daily work, clinicians use Creatinine Clearance to adjust drug dose, to screen for renal impairment, and to watch renal function over time in high risk patients.

What Is The Cockcroft Gault Equation

The Cockcroft Gault equation is a classic formula to estimate Creatinine Clearance from age, weight, sex, and serum creatinine. It was first described in the 1970s and has been used for decades in clinical drug dosing.

The standard Cockcroft Gault equation for adults is:

CrCl (mL/min) = (140 - age in years) × weight in kilograms ÷ (72 × serum creatinine in mg/dL). For females, multiply the result by 0.85.

The 0.85 factor accounts for lower average muscle mass in females in the original study group. The result is an estimate ofmedica Creatinine Clearance in mL per minute, not normalised to body surface area.

How This Creatinine Clearance Calculator Works

The calculator on this page applies the Cockcroft Gault equation step by step. It also makes unit changes for weight and serum creatinine so that you do not have to do conversions by hand.

  1. You enter age, sex, weight, and serum creatinine.
  2. You can choose weight in kilograms or pounds and creatinine in mg/dL or µmol/L.
  3. The tool converts pounds to kilograms and µmol/L to mg/dL.
  4. The calculator picks the weight type, such as actual, ideal, or adjusted, based on your selection.
  5. It computes CrCl with the Cockcroft Gault equation.
  6. If height is present it also estimates body surface area and a CrCl normalised to 1.73 m².

The result card shows both the main CrCl value and a breakdown of key factors. This makes it easier to explain the estimate to trainees and to cross check calculations.

Weight Choices In Cockcroft Gault

There is long debate on which weight to use in obesity, low body weight, and other special cases. Different hospitals use different policies. This Creatinine Clearance calculator lets you pick from three weight options.

Actual body weight

This is the patient current scale weight. It is the original form of the Cockcroft Gault equation and is still used by many drug labels. It may over estimate true kidney function in severe obesity.

Ideal body weight

Some renal dosing guides suggest ideal body weight as the default weight when BMI is high. This calculator can estimate ideal weight when you enter height. It uses common IBW formulas based on sex and height in centimeters.

Adjusted body weight

Adjusted body weight sits between actual and ideal. Some centers use adjusted weight when body mass is well above ideal, often when BMI is more than 30. The goal is to avoid over estimating clearance in obesity while still accounting for extra lean mass.

Always follow your local renal dosing policy when you choose which weight to use in the Cockcroft Gault equation.

How To Use The Creatinine Clearance Calculator

Step 1: Gather lab and vital data

Before you open the tool, collect the most recent serum creatinine, the patient age, sex, current weight, and height if known. Make sure the creatinine value is recent and reasonably stable.

Step 2: Enter age, sex, weight, and creatinine

Type age in years and serum creatinine in the same unit that appears on the lab report. If the report uses µmol/L, select that from the drop down so the tool can convert to mg/dL. Choose the weight unit and enter the value.

Step 3: Choose the weight type

For many adults without extreme BMI you can leave weight type as actual body weight. If your protocol suggests ideal or adjusted weight in obesity you can change it in the drop down. The calculator will update the CrCl estimate.

Step 4: Review the result and renal band

The main number shows Creatinine Clearance in mL per minute. The tool also labels a rough renal function band such as mild, moderate, or severe impairment. These bands are for quick review only and do not map to every drug label.

Step 5: Apply local dosing rules

Once you have a CrCl estimate you still need to check your local dosing tables, drug monograph, or pharmacy software. Always adjust dose based on the full clinical picture, not on Creatinine Clearance alone.

Creatinine Clearance Ranges And Renal Function Bands

Many drug guides use broad ranges of Creatinine Clearance to group renal function. Exact cutoffs differ across sources, but a common set of bands is:

  • CrCl 90 mL/min or more: likely normal or high kidney function.
  • CrCl 60 to 89 mL/min: mild loss of function.
  • CrCl 30 to 59 mL/min: moderate loss.
  • CrCl 15 to 29 mL/min: severe loss.
  • CrCl less than 15 mL/min: very severe loss or kidney failure.

The calculator uses these bands to tag the result. They are for quick review only. Use full guidelines when you make treatment choices.

Limitations Of The Cockcroft Gault Equation

While Cockcroft Gault remains popular for drug dosing, it has several limits.

  • It was derived from a small group of mainly male patients.
  • It can be less accurate at very low or very high body size.
  • It assumes stable serum creatinine and steady kidney function.
  • It may mislead in acute kidney injury or during fast change in renal status.
  • It can differ from eGFR values that use MDRD or CKD EPI equations.

Many labs now report eGFR with CKD EPI. Yet many drug labels still reference Creatinine Clearance from Cockcroft Gault. In practice you often need to look at both values and consider the whole case.

Frequently Asked Questions About This Creatinine Clearance Calculator

Is this Cockcroft Gault calculator for adults only

Yes. The equation and this tool are for adults. For children you should use pediatric renal equations and pediatric dosing guides that fit your health system.

Does the calculator support µmol per liter

Yes. You can choose µmol/L as the creatinine unit. The calculator then converts to mg/dL internally using a standard factor so that the Cockcroft Gault formula stays correct.

Can I use this calculator for dialysis patients

No. In dialysis and in very advanced kidney failure, serum creatinine is not a good stand alone guide. Dosing should follow specific dialysis drug schedules and specialist input.

Why does the calculator show a value per minute and per 1.73 m²

The original Cockcroft Gault result is in mL per minute. Many eGFR formulas use mL per minute per 1.73 m². The tool shows both so that you can compare with lab eGFR values while still using the standard CrCl figure for drug dosing.

Is this calculator a replacement for clinical judgment

No. It is a learning and support tool. It can help you avoid math errors and improve speed, but the final choice on doses and risk must come from trained clinicians who know the full case.

Start Using The Creatinine Clearance Cockcroft Gault Calculator

Enter age, sex, weight, and serum creatinine into the calculator at the top of this page. Choose units that match your lab and pick the weight type your policy uses. Review the Creatinine Clearance value and renal band, then apply your local renal dosing rules. Use this Cockcroft Gault equation tool as part of a safe, clear, and consistent approach to drug dosing in patients with kidney disease.