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Creatinine Clearance Calculator (Cockcroft-Gault)
Creatinine clearance (CrCl) is estimated with the Cockcroft-Gault equation: (140 − age) × weight in kg ÷ (72 × serum creatinine in mg/dL), multiplied by 0.85 for women. A 60-year-old man at 80 kg with a creatinine of 1.0 mg/dL has a CrCl of about 89 mL/min. The calculator below shows actual, ideal and adjusted body weight side by side.
Prepared by Prospyr · Reviewed October 3, 2026 · Free, no sign-up, runs in your browser
Height is only used to find ideal and adjusted body weight.
Cockcroft-Gault creatinine clearance (actual weight)
89mL/min
Same equation, three weights. Which weight a protocol uses is set by that protocol, not by this page.
Decision support only; it does not replace clinical judgment. It is not a drug dose or dosing adjustment.
Side by side: actual, ideal and adjusted weight
| Weight used | Weight (kg) | CrCl (mL/min) | How it is found |
|---|---|---|---|
| Actual body weight | 79.8 | 89 | Weight as measured |
| Ideal body weight (Devine) | 73 | 81 | 50 + 2.3 kg per inch over 5 ft |
| Adjusted body weight | 75.7 | 84 | IBW + 0.4 × (actual − IBW) |
CrCl = (140 − age) × weight (kg) ÷ (72 × serum creatinine in mg/dL). Ideal weight is 73 kg for this height. The result is in mL/min, not indexed to body surface area.
Cockcroft-Gault creatinine clearance formula
CrCl (mL/min) = (140 − age) × weight (kg) ÷ (72 × Scr) × 0.85 if female
Age is in years, weight is in kilograms and Scr is serum creatinine in mg/dL. If the lab reports µmol/L, divide by 88.4 first. The equation comes from a 1976 paper by Cockcroft and Gault, and many references and labels still cite it. It returns mL/min and is not scaled to body surface area, which is why it differs from an eGFR.
Actual, ideal and adjusted body weight side by side
The weight you put into the equation changes the answer, sometimes by a lot in a larger patient. The calculator runs the same equation three times.
- Actual body weight: the measured weight.
- Ideal body weight (Devine): 50 kg (men) or 45.5 kg (women) + 2.3 kg per inch over 5 feet.
- Adjusted body weight: ideal weight + 0.4 × (actual − ideal). Defined only when actual weight is above ideal.
Pai and Paloucek traced the ideal-weight equations back to height-weight tables and note that the common versions agree closely. A 2011 meta-analysis (Wilhelm and Kale-Pradhan, 13 trials, 1,197 patients) compared the weights against measured clearance and found no single weight that works everywhere. Which one applies is a protocol question, so this page shows all of them and leaves the choice to you.
Worked example: CrCl for a 100 kg man
A 60-year-old man, 5 ft 10 in (70 inches), 100 kg, creatinine 1.0 mg/dL.
| Weight used | Weight | Math | CrCl |
|---|---|---|---|
| Actual | 100 kg | 80 × 100 ÷ 72 | 111 mL/min |
| Ideal (Devine) | 73.0 kg | 50 + 2.3 × 10 = 73; 80 × 73 ÷ 72 | 81 mL/min |
| Adjusted | 83.8 kg | 73 + 0.4 × 27 = 83.8; 80 × 83.8 ÷ 72 | 93 mL/min |
Same patient, same lab value, three results from 81 to 111 mL/min. For a woman, multiply each result by 0.85 and use 45.5 kg as the starting ideal weight. A 60-year-old woman at 80 kg with a creatinine of 1.0 mg/dL has a CrCl of 75.6 (about 76) mL/min on actual weight.
CrCl vs eGFR, and what this page leaves out
Use the eGFR calculator for the CKD-EPI 2021 estimate and KDIGO category. This page does only the Cockcroft-Gault arithmetic. It does not choose a weight, convert clearance into a drug dose, or say whether a patient is suitable for a procedure or medication. Those calls come from the prescriber, the product label and the practice protocol.
If your team records labs and weights with each visit, Prospyr's charting keeps them with the rest of the chart. The med spa software page covers the wider workflow.
Frequently asked questions
What is the Cockcroft-Gault formula?
CrCl (mL/min) = (140 − age in years) × weight in kg ÷ (72 × serum creatinine in mg/dL), then × 0.85 for women. It was published by Cockcroft and Gault in Nephron in 1976. This calculator uses it exactly as written.
Which weight should I use: actual, ideal or adjusted?
That is set by your protocol or the reference you follow, so this calculator shows all three and does not pick one. A 2011 meta-analysis of 13 trials found total body weight overestimated measured clearance, ideal body weight underestimated it, and adjusted weight with a 0.3 or 0.4 factor came closer in obese patients. Results varied widely between studies.
How is ideal body weight calculated?
This page uses the Devine formula: 50 kg for men or 45.5 kg for women, plus 2.3 kg for every inch of height over 5 feet. Adjusted body weight is ideal weight plus 0.4 times the difference between actual and ideal weight. Adjusted weight is only shown when actual weight is above ideal weight.
How do I convert creatinine from µmol/L to mg/dL?
Divide µmol/L by 88.4. A creatinine of 88.4 µmol/L equals 1.0 mg/dL. The calculator converts for you when you switch units, so you can enter the value as it appears on the lab report.
What is the difference between creatinine clearance and eGFR?
Creatinine clearance (Cockcroft-Gault) uses age, actual or adjusted weight, creatinine and sex, and is reported in mL/min. eGFR (CKD-EPI) is standardized to 1.73 m² of body surface area. They are separate estimates, so the numbers will not match. For the eGFR, see our eGFR calculator.
Does this calculator give a drug dose?
No. It returns an estimated clearance and nothing else. It does not suggest a drug, a dose or a dose change, and it does not say whether a patient is cleared for anything. Those decisions come from the prescriber, the product label and your protocol.
Sources and scope
- Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31-41
Peer-reviewed. The original equation.
- Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother 2000;34:1066-9
Peer-reviewed. Background on the Devine ideal body weight equations and why the common versions agree.
- Wilhelm SM, Kale-Pradhan PB. Estimating creatinine clearance: a meta-analysis. Pharmacotherapy 2011;31:658-64
Peer-reviewed. Compares actual, ideal and adjusted (0.3 or 0.4 factor) weights against measured clearance in 13 trials.
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int 2024
Context for eGFR versus measured and estimated clearance.
Decision support only; it does not replace clinical judgment. This is the published Cockcroft-Gault arithmetic. It does not recommend a drug, dose or dose adjustment, a weight to use, or clearance for any procedure.