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Creatinine Clearance Calculator
Cockcroft-Gault creatinine clearance for renal drug dosing, with ideal/adjusted body weight and the CrCl-vs-eGFR distinction — an estimate for dose adjustment, not dosing advice. Accurate, instant and free — for United States.
What these mean:
What these mean:
What these mean:
What these mean:
Creatinine clearance ≈ 64.8 mL/min (Cockcroft-Gault, actual body weight 80 kg). General renal-dosing tier: ≥ 50 mL/min (mild / no impairment for most drugs). An estimate for dose adjustment, not dosing advice — clinician decision.
Creatinine clearance
64.8 mL/min
Ideal body weight
70.7 kg
Weight used
80 kg
Renal-dosing tier: ≥ 50 mL/min — mild or no impairment for most drugs
CrCl (drug dosing) is not the same as eGFR (CKD staging)
An estimate for dose adjustment, not dosing advice
How we calculate this
Reviewed by Reckonist Editorial · Last reviewed July 2026. Figures follow the methods and sources set out in our editorial standards.
Uses the Cockcroft-Gault equation (1976) with Devine ideal body weight. An estimate for renal dose adjustment, not dosing advice — clinician decision.
Cockcroft-Gault · Devine IBW · NKF / MDCalc
Staging kidney function or tracking blood sugar too? See the eGFR Calculator and the A1C Calculator.
The Cockcroft-Gault equation
From age, weight, sex and serum creatinine, this tool estimates creatinine clearance (CrCl) with the Cockcroft-Gault equation — the traditional standard for renal drug dosing. It also computes ideal body weight (for obese patients) and shows which general renal-dosing tier the result lands in.
Cockcroft-Gault CrCl
mL/min (not BSA-indexed)
CrCl = [(140 − age) × kg × (0.85 ♀)] ÷ (72 × Scr mg/dL)
Estimates clearance in mL/min for drug dosing. Multiply by 0.85 for females. µmol/L creatinine is divided by 88.42 to mg/dL first.
Ideal / Adjusted body weight
Devine, for obesity
IBW = 50 ♂ / 45.5 ♀ + 2.3 × (in − 60); ABW = IBW + 0.4 × (actual − IBW)
In obesity, actual weight overestimates CrCl — use IBW or adjusted body weight. The weight basis is drug-specific.
- 1Apply the formula: (140 − 70) × 80 ÷ (72 × 1.2) = 5,600 ÷ 86.4 = ≈ 64.8 mL/min.
- 2Female factor: × 0.85 → ≈ 55.1 mL/min. Both land in the ≥ 50 mL/min tier — mild or no impairment for most drugs.
CrCl for drug dosing, eGFR for CKD staging
The most common confusion is treating CrCl and eGFR as interchangeable. They are not. CrCl (Cockcroft-Gault) is the traditional standard for renal drug dosing — most pharmacokinetic studies and FDA/EMA labels use it, and it is not BSA-indexed. eGFR (CKD-EPI 2021) is for CKD staging and diagnosis and is BSA-indexed (mL/min/1.73m²).
When in doubt: CrCl for dosing, eGFR for classification
Ideal and adjusted body weight
At a normal BMI, actual body weight is fine. In obesity, actual weight overestimates creatinine clearance, so ideal body weight (Devine) or adjusted body weight is generally preferred. Devine IBW is 50 kg (♂) or 45.5 kg (♀) plus 2.3 kg per inch over 60 inches; adjusted body weight is IBW + 0.4 × (actual − IBW). One caveat worth repeating: the weight basis is drug-specific — agents such as vancomycin and aminoglycosides are often dosed on actual weight per protocol, so do not blanket-apply IBW.
General renal-dosing tiers
Many drug labels adjust doses around common CrCl breakpoints: roughly ≥ 50 mL/min (mild or no impairment for most drugs), 30–49 mL/min (moderate — many drugs need a reduced dose), 15–29 mL/min (severe — major dose reduction or avoidance) and < 15 mL/min (kidney-failure / dialysis-range dosing). DOACs (apixaban, rivaroxaban, dabigatran) and many antibiotics key off these tiers. The tier shown is educational — always check the specific drug label, not a generic number.
mg/dL vs µmol/L creatinine
US labs report serum creatinine in mg/dL; most other countries report µmol/L. Divide µmol/L by 88.42 to get mg/dL (106.1 µmol/L ≈ 1.2 mg/dL). Cockcroft-Gault is defined in mg/dL, so this tool converts µmol/L before computing — a mislabelled creatinine would badly skew the estimate, which matters when the output guides drug dosing.
Frequently asked questions
The Cockcroft-Gault equation is CrCl (mL/min) = [(140 − age) × weight in kg × (0.85 if female)] ÷ (72 × serum creatinine in mg/dL). For a 70-year-old man weighing 80 kg with a creatinine of 1.2 mg/dL, that is (140 − 70) × 80 ÷ (72 × 1.2) = 5,600 ÷ 86.4 ≈ 64.8 mL/min. For a woman the same inputs give ≈ 55.1 mL/min after the 0.85 factor. It is an estimate for dose adjustment, not dosing advice.
They answer different questions. CrCl from Cockcroft-Gault is the traditional standard for renal drug dosing — most pharmacokinetic studies and FDA/EMA drug labels use it, and it is not indexed to body surface area (BSA). eGFR (CKD-EPI 2021) is used to stage and diagnose chronic kidney disease and is BSA-indexed (mL/min/1.73m²). A simple rule: use CrCl for drug dosing, and eGFR for CKD classification. Because they use different equations and units, the two numbers can differ for the same patient.
At a normal BMI, actual body weight is fine. In obese patients, actual weight overestimates creatinine clearance, so ideal body weight (Devine) or adjusted body weight is generally preferred. Adjusted body weight = IBW + 0.4 × (actual − IBW). Important caveat: the weight basis is drug-specific — some agents such as vancomycin and aminoglycosides are dosed on actual body weight per protocol, so do not blanket-apply IBW.
Many drug labels adjust doses around common creatinine-clearance breakpoints: roughly ≥ 50 mL/min (mild or no impairment for most drugs), 30–49 mL/min (moderate — many drugs need a reduced dose), 15–29 mL/min (severe — major dose reduction or avoidance), and < 15 mL/min (kidney-failure / dialysis-range dosing). DOACs such as apixaban, rivaroxaban and dabigatran, and many antibiotics, key off these tiers. The tiers are educational — always check the specific drug label, not a generic number.
US labs report serum creatinine in mg/dL; most other countries report µmol/L. To convert, divide µmol/L by 88.42 to get mg/dL (for example, 106.1 µmol/L ≈ 1.2 mg/dL). Cockcroft-Gault is defined in mg/dL, so this calculator converts µmol/L values before computing. Getting the unit right matters — a mislabelled creatinine would badly skew the estimate.
No. It is a free, private estimate that runs entirely in your browser, intended for dose adjustment, not dosing advice. Cockcroft-Gault is unreliable when creatinine is unstable (acute kidney injury) and at extremes of muscle mass; in the elderly a deceptively normal creatinine can mask low muscle mass and overestimate clearance. It is not a diagnosis and not a clearance to dose — the decision belongs with a clinician.
Method, standards & references
Methodology: CrCl (mL/min) = [(140 − age) × weight kg × (0.85 if female)] ÷ (72 × serum creatinine mg/dL); Cockcroft-Gault (1976), not BSA-indexed, for renal drug dosing. Devine ideal body weight = 50 kg (♂) / 45.5 kg (♀) + 2.3 kg per inch over 60 in; adjusted body weight = IBW + 0.4 × (actual − IBW). Units: µmol/L ÷ 88.42 = mg/dL. eGFR (CKD-EPI 2021) is a separate, BSA-indexed equation for CKD staging. All calculations run client-side and nothing is stored. An estimate for dose adjustment, not dosing advice.
Cross-links
How we calculate this
Reviewed by Reckonist Editorial · Last reviewed July 2026. Figures follow the methods and sources set out in our editorial standards.
Creatinine clearance is estimated with the Cockcroft-Gault equation (1976) and Devine ideal body weight. CrCl is for renal drug dosing (FDA/EMA labels, not BSA-indexed), whereas eGFR (CKD-EPI 2021) is for CKD staging. This is general health information for education, an estimate for dose adjustment — not dosing advice, not a diagnosis. It is unreliable in acute kidney injury and at extremes of muscle mass. Always confirm with a clinician.
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