Creatinine Clearance (CrCl) Calculator
This free creatinine clearance calculator estimates kidney function using the Cockcroft-Gault equation, based on age, weight, sex, and serum creatinine. CrCl is widely used to assess renal function and to adjust medication doses for drugs cleared by the kidneys. Enter the patient's values and the calculator returns the estimated creatinine clearance in mL/min.
How to Use the CrCl Calculator
- Enter age, weight, and sex.
- Enter the serum creatinine (mg/dL).
- Calculate — see the estimated creatinine clearance.
The Cockcroft-Gault Equation
CrCl = ((140 − age) × weight) ÷ (72 × serum creatinine)
For females, multiply the result by 0.85. Weight is in kilograms and serum creatinine in mg/dL. For example, a 60-year-old man weighing 80 kg with a creatinine of 1.0 mg/dL has a CrCl of ((140 − 60) × 80) ÷ (72 × 1.0) ≈ 88.9 mL/min.
Interpreting Creatinine Clearance
| CrCl (mL/min) | General Interpretation |
|---|---|
| ≥ 90 | Normal kidney function |
| 60–89 | Mildly reduced |
| 30–59 | Moderately reduced |
| 15–29 | Severely reduced |
| < 15 | Kidney failure |
Why CrCl Matters
- Drug dosing: many medications require dose adjustment based on CrCl.
- Kidney assessment: tracks renal function over time.
- Safety: avoids drug accumulation in patients with reduced clearance.
Note: This calculator is an educational tool. Clinical decisions should account for the full patient context and current guidelines. Which weight to use (actual, ideal, or adjusted) can affect the result.
Frequently Asked Questions
What is creatinine clearance?
Creatinine clearance estimates how well the kidneys filter creatinine from the blood, used as a measure of kidney function and to adjust drug doses.
What is the Cockcroft-Gault equation?
It estimates CrCl as ((140 − age) × weight) ÷ (72 × serum creatinine), multiplied by 0.85 for females.
What is a normal creatinine clearance?
A CrCl of about 90 mL/min or higher is generally considered normal, with lower values indicating reduced kidney function.
Why is CrCl used for drug dosing?
Many medications are cleared by the kidneys, so a lower CrCl means slower clearance and a need to reduce the dose to avoid accumulation.
Is this CrCl calculator free?
Yes — it is completely free, requires no signup, and estimates creatinine clearance with the Cockcroft-Gault equation.