Creatinine Clearance Calculator
Estimate Creatinine Clearance values for health, wellness, and lifestyle planning.
This creatinine clearance calculator estimates kidney filtration function using the Cockcroft-Gault formula, based on age, weight, sex, and serum creatinine level - a calculation commonly referenced for kidney function screening and certain medication dosing decisions.
Enter your age, weight, sex, and serum creatinine, and the calculator returns an estimated creatinine clearance in mL/min.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| Male, 55 years, 80 kg, serum creatinine 1.0 mg/dL | CrCl ≈ 94.4 mL/min | CrCl = [(140 − 55) × 80] ÷ (72 × 1.0) = (85 × 80) ÷ 72 = 6,800 ÷ 72 ≈ 94.4 mL/min. |
| Female, 65 years, 65 kg, serum creatinine 1.1 mg/dL | CrCl ≈ 52.3 mL/min | CrCl = [(140 − 65) × 65] ÷ (72 × 1.1) × 0.85 = (75 × 65) ÷ 79.2 × 0.85 = 61.6 × 0.85 ≈ 52.3 mL/min. |
The Cockcroft-Gault Formula
Creatinine clearance (mL/min) = [(140 - age) x weight (kg)] / (72 x serum creatinine (mg/dL)), multiplied by 0.85 for women. Lower creatinine clearance values generally indicate reduced kidney filtration function, since less creatinine is being cleared from the blood per minute.
Why Age and Weight Are Both Factors
Muscle mass produces creatinine at a fairly steady rate, and both age (muscle mass tends to decline with age) and weight (a rough proxy for muscle mass) affect how much creatinine a person's body typically generates - the formula adjusts for these factors to produce a more individualized estimate than serum creatinine alone would provide.
How to Use the Creatinine Clearance Calculator
- Open the Creatinine Clearance Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the creatinine clearance calculator works.
Frequently Asked Questions
What is the Cockcroft-Gault formula used for?
It estimates creatinine clearance, a measure of kidney filtration function, using age, weight, sex, and serum creatinine - it's commonly referenced for kidney function screening and certain medication dosing calculations.
What does a low creatinine clearance mean?
A lower value generally suggests reduced kidney filtration function, though the result should be interpreted by a healthcare provider alongside other clinical information, not used alone for diagnosis.
Why does the formula multiply by 0.85 for women?
The adjustment accounts for average differences in muscle mass between sexes, since creatinine clearance estimates are influenced by how much creatinine the body typically produces from muscle metabolism.
How do I use this creatinine clearance calculator?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Creatinine Clearance Calculator calculate?
Estimate Creatinine Clearance values for health, wellness, and lifestyle planning. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this creatinine clearance use?
The formula is: CrCl = [(140 − Age) × Weight(kg)] ÷ (72 × Serum Creatinine) × 0.85 (if female). Donald Cockcroft and Henry Gault published this formula in 1976 based on data from 249 Canadian patients, developing it specifically because directly measuring kidney filtration rate in a clinical lab was impractical for routine use - decades later, it remains widely referenced for medication dosing decisions despite newer equations like CKD-EPI now being preferred for general kidney function staging.
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Last updated: September 27, 2026.