cockroft gault calculator

What is the Cockcroft-Gault calculator?

The Cockcroft-Gault calculator estimates creatinine clearance (CrCl), an approximation of kidney filtration function in adults. Clinicians often use this value to help with medication dosing, especially for drugs that are eliminated through the kidneys.

While many people search for a “cockroft gault calculator,” the standard spelling is Cockcroft-Gault. It remains one of the most widely referenced bedside equations in pharmacology.

Cockcroft-Gault formula

For adults, the classic formula is:

CrCl (mL/min) = [(140 − age) × weight (kg)] ÷ [72 × serum creatinine (mg/dL)]

For females, multiply the result by 0.85.

Inputs used in this tool

• Age in years
• Sex at birth (male/female correction factor)
• Weight in kg or lb (converted to kg automatically)
• Serum creatinine in mg/dL or µmol/L (converted to mg/dL automatically)

How to use this calculator

1. Enter your age.
2. Select sex at birth.
3. Enter your current body weight and unit.
4. Enter serum creatinine and the correct lab unit.
5. Click Calculate to view estimated CrCl and interpretation.

Interpreting your estimated CrCl

This tool gives a practical interpretation range:

• 90+ mL/min: usually within normal filtration range
• 60–89 mL/min: mildly reduced
• 30–59 mL/min: moderately reduced
• 15–29 mL/min: severely reduced
• <15 mL/min: kidney failure range

These ranges are educational and not a diagnosis by themselves. Clinical context and repeat labs matter.

Important limitations

When Cockcroft-Gault may be less accurate

• Very low or very high muscle mass
• Acute kidney injury (rapidly changing creatinine)
• Pregnancy
• Extremes of body size
• Unstable lab values or dehydration

In many settings, professionals compare this estimate with other measures such as CKD-EPI eGFR, cystatin C, urine studies, and direct clinical assessment.

Cockcroft-Gault vs eGFR

eGFR equations (like CKD-EPI) are often used to stage chronic kidney disease, while Cockcroft-Gault has long been used in drug-dosing references and package inserts. Depending on the medication, the recommended method may still specifically require Cockcroft-Gault CrCl.

Medication dosing caution

Never adjust prescription medications on your own based only on an online calculation. Dose changes should be made by a qualified clinician who can evaluate your full chart, trend data, hydration status, and comorbidities.

FAQ

Is this calculator for children?

No. The Cockcroft-Gault equation is intended for adults.

Can I use µmol/L instead of mg/dL?

Yes. This calculator converts µmol/L to mg/dL automatically using standard conversion.

Does this replace a doctor visit?

No. It is an informational estimate and should not replace professional medical advice.