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Creatinine clearance
Example66.5mL/min
Mildly decreased
Scale: 0–120 mL/min
Why ideal body weight: Actual weight is 102% of ideal body weight and BMI is 23.7 kg/m², so ideal body weight is conventionally used.
This is convention, not a validated equation. Institutional protocol takes precedence.
CrCl = [(140 − age) × weight] / (72 × Scr)
= [(140 − 68) × 73.2] / (72 × 1.10)
= 66.53 mL/min
Scr used: 1.10 mg/dL
Weight basis: ideal body weightThese bands are a drug-dosing reference applied to Cockcroft-Gault CrCl. They are not KDIGO CKD stages, which are defined on eGFR in mL/min/1.73 m².
Creatinine clearance is calculated with the Cockcroft-Gault equation: CrCl (mL/min) = [(140 − age) × weight in kg] / (72 × serum creatinine in mg/dL), multiplied by 0.85 for females. Published by Cockcroft and Gault in Nephron in 1976, it estimates clearance from four variables and is the figure most renal drug-dosing guidance is written against.
Overview
Creatinine is a waste product of muscle metabolism, cleared from the blood almost entirely by the kidneys. Creatinine clearance (CrCl) expresses how much blood the kidneys clear of creatinine per minute, in mL/min — the standard proxy for renal function in clinical practice.
It matters most for renal drug dosing. A large share of medicines are cleared renally, and their labels specify dose adjustments at defined clearance thresholds. Getting the number wrong in either direction has consequences: too high risks toxicity, too low risks underdosing an infection or an anticoagulant.
This CrCl calculator is built for the people who make those decisions — clinical pharmacists, prescribers, nurses, and students learning renal dosing. If you need a size-indexed figure for CKD staging instead, use the eGFR calculator; for a direct measurement, use the 24-hour urine calculator.
Benefits
The result updates on every keystroke. Nothing to click, nothing to wait for.
mg/dL or µmol/L, kg or lb, cm or in — converted exactly, never approximated.
Actual, ideal and adjusted side by side, with the conventional choice marked and explained.
No account, no server round-trip, no logging. Safe to use with real patient values.
Guide
Sex applies the 0.85 female factor; age drives the (140 − age) term that encodes the expected age-related decline.
Add height too. The calculator then shows actual, ideal and adjusted body weight together and marks the conventional choice for this patient.
Toggle mg/dL or µmol/L. Conversion is exact (1 mg/dL = 88.4 µmol/L), so both paths give an identical result.
The figure appears immediately in mL/min, with mL/hour, a BSA-normalised value and a colour-coded renal function band.
Every substituted value is displayed so you can check the arithmetic rather than trust it — useful for teaching, and for double-checking a borderline result.
Within ~20% of a threshold that changes management? Consider a measured clearance or cystatin C instead of the estimate.
Formula
CrCl (mL/min) = [(140 − age) × weight(kg)] / (72 × Scr)
× 0.85 if femaleScr = serum creatinine in mg/dL. Age in years. Weight in kilograms — see the weight-basis rules below.
Source: Cockcroft DW, Gault MH. Nephron. 1976;16(1):31–41.
CrCl (mL/min) = [(140 − age) × weight(kg) × F] / Scr F = 1.23 (male) · F = 1.04 (female)
Scrin µmol/L. This calculator converts exactly (1 mg/dL = 88.4 µmol/L) rather than using the rounded 1.23 / 1.04 shortcuts, so both unit paths agree to the decimal.
| Term | What it represents |
|---|---|
| 140 − age | The expected age-related decline in filtration — roughly 1 mL/min per year from about age 40. |
| × weight (kg) | A proxy for muscle mass, which determines creatinine production. The assumption that breaks in obesity. |
| ÷ 72 | The fitting constant that reconciled the equation with measured clearances in the original 1976 cohort. |
| ÷ Scr | Serum creatinine. Because it sits in the denominator, the relationship to clearance is curvilinear, not linear. |
| × 0.85 | Applied for females, to account for lower average muscle mass and therefore lower creatinine production. |
Simple formula
(140 minus age) times weight in kg, divided by 72 times creatinine in mg/dL. Then take 85% of it if the patient is female.
For a 70 kg adult with a creatinine of exactly 1.0 mg/dL, the equation collapses to (140 − age) × 0.97— so clearance is roughly “140 minus age” in mL/min. A 60-year-old lands near 78; an 85-year-old near 53. It is a useful sanity check on a result you have just calculated, not a substitute for calculating it.
| Serum creatinine | Age 40 | Age 60 | Age 80 |
|---|---|---|---|
| 0.8 mg/dL | 121 mL/min | 97 mL/min | 73 mL/min |
| 1.0 mg/dL | 97 mL/min | 78 mL/min | 58 mL/min |
| 1.5 mg/dL | 65 mL/min | 52 mL/min | 39 mL/min |
| 2.0 mg/dL | 49 mL/min | 39 mL/min | 29 mL/min |
| 3.0 mg/dL | 32 mL/min | 26 mL/min | 19 mL/min |
Examples
68-year-old man on a medical ward, stable renal function, being started on a renally cleared antibiotic.
IBW = 50 + 2.3 × (70.1 − 60) = 73.2 kg
BMI = 75 / 1.78² = 23.7 → use ideal weight
CrCl = [(140 − 68) × 73.2] / (72 × 1.1)
= 5,270 / 79.266.5mL/min
Mildly decreased. Using actual weight instead would give 68.2 mL/min — a small difference at normal BMI.
55-year-old man, BMI 39, where the weight-basis choice changes the dosing band.
IBW = 50 + 2.3 × (68.9 − 60) = 70.5 kg
BMI = 120 / 1.75² = 39.2 → use adjusted weight
AdjBW = 70.5 + 0.4 × (120 − 70.5) = 90.3 kg
CrCl = [(140 − 55) × 90.3] / (72 × 1.2)
= 7,673 / 86.488.8mL/min
Actual weight would have given 118.1 mL/min — a 33% overestimate, and a different dosing decision for several drugs.
82-year-old woman, low muscle mass, with a serum creatinine that looks reassuringly normal.
IBW = 45.5 + 2.3 × (62.2 − 60) = 50.6 kg
Actual (46) < IBW (50.6) → use actual weight
CrCl = [(140 − 82) × 46] / (72 × 0.9) × 0.85
= 2,668 / 64.8 × 0.8535.0mL/min
A normal-looking creatinine of 0.9 mg/dL alongside moderately decreased clearance. This is the classic elderly pitfall.
Each of these is worked through in more depth in the guides: adjusting CrCl for obese patients and creatinine clearance in elderly patients.
Accuracy
See also: ten common mistakes when calculating creatinine clearance.
Like other widely used clinical calculators — including MDCalc and GlobalRPH — this tool implements the standard Cockcroft-Gault equation, so a given set of inputs produces the same core result. The differences are in what surrounds it: unit flexibility on both weight and creatinine, all three body-weight bases shown at once, and the result interpreted rather than simply displayed. This site is not affiliated with, endorsed by, or connected to any of those services.
Primary source: Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31–41.
Full equation registry on the methodology page.
Details
Male: IBW (kg) = 50.0 + 2.3 × (height in inches − 60) Female: IBW (kg) = 45.5 + 2.3 × (height in inches − 60)
Source: Devine BJ. Drug Intell Clin Pharm. 1974;8:650–5.
AdjBW (kg) = IBW + 0.4 × (actual weight − IBW)
The 0.4 correction factor reflects that adipose tissue contributes some, but not proportional, clearance capacity.
Source: Bauer LA et al. Clin Pharmacol Ther. 1983;33(4):519–25.
| Patient | Weight to use | Why |
|---|---|---|
| Below ideal weight | Actual | Using IBW would credit clearance the patient does not have. |
| Normal BMI (< 25) | Ideal | The equation was derived against a broadly normal-weight cohort. |
| > 120% of ideal weight | Adjusted | Actual weight starts to overestimate clearance materially. |
| BMI ≥ 30 | Adjusted | Adipose tissue produces little creatinine; actual weight overestimates. |
| Extreme obesity | Consider Salazar-Corcoran | An obesity-specific equation, validated in obese subjects. |
Normal
≥ 90 mL/min
Mildly decreased
60–89.9 mL/min
Moderately decreased
30–59.9 mL/min
Severely decreased
15–29.9 mL/min
Kidney failure
0–14.9 mL/min
| Age | Male (mL/min) | Female (mL/min) |
|---|---|---|
| 20–29 | ≈ 110–140 | ≈ 100–130 |
| 40–49 | ≈ 95–125 | ≈ 85–115 |
| 60–69 | ≈ 75–105 | ≈ 65–95 |
| 80+ | ≈ 50–80 | ≈ 45–75 |
| Threshold | Typical significance |
|---|---|
| < 60 mL/min | Where many drug labels first specify review. |
| < 50 mL/min | Common DOAC dose-reduction point — check the specific product. |
| < 30 mL/min | Substantial adjustment for many antimicrobials; some contraindicated. |
| < 15 mL/min | Kidney failure range; dialysis-specific dosing. |
Relationships
An estimate in mL/min, not indexed to body surface area. This is the figure most renal drug-dosing guidance is written against.
Which should guide dosing? →An estimate in mL/min/1.73 m² — indexed to body surface area, used for CKD staging. Converting means de-indexing by BSA, and even then the two are not interchangeable.
Convert CrCl and eGFR →An actual measurement from a timed collection. More accurate in principle — but only as good as the collection.
Calculate measured CrCl →The distinction is unpacked in CrCl vs eGFR and understanding serum creatinine.
Applications
Verifying renal dose adjustments at the point of dispensing with a CrCl calculator, and screening for drugs that need review as clearance falls.
Checking a CrCl calculator result against a product label threshold before prescribing, particularly for anticoagulants and antimicrobials.
Sanity-checking an ordered dose against a patient’s renal function with a CrCl calculator before administration.
Learning why the weight-basis choice matters — this CrCl calculator shows the working rather than hiding it behind a result.
More calculators
CKD-EPI 2021 creatinine, cystatin C and combined equations, plus Schwartz for children and a CrCl comparison.
Open calculatorWeight-basis selection, Salazar-Corcoran, amputation correction, paediatric equations and mL/hour output.
Open calculatorDevine ideal body weight, Bauer adjusted body weight and BMI, with the conventional basis for Cockcroft-Gault marked.
Open calculatorMeasured clearance from a timed collection, with a collection-adequacy check and BSA normalisation.
Open calculatorPrefer to browse? See the full HTML sitemap or the guides index.
FAQ
The questions clinicians most often search for. Every answer on this site is aggregated on the FAQ hub.
CrCl (mL/min) = [(140 − age) × weight in kg] / (72 × serum creatinine in mg/dL), multiplied by 0.85 for females. This is the Cockcroft-Gault equation (Cockcroft & Gault, Nephron 1976). Which weight you use matters: ideal body weight for normal-weight patients, adjusted body weight when BMI is 30 or above.
Estimated CrCl is calculated from four variables — age, sex, body weight and serum creatinine — using Cockcroft-Gault. It is an estimate of clearance, not a measurement. Measured creatinine clearance requires a timed urine collection, which this site calculates separately.
Divide [(140 − age) × weight in kg] by (72 × serum creatinine in mg/dL), then multiply by 0.85 for females. If your laboratory reports creatinine in µmol/L, divide by 88.4 to convert to mg/dL first — or switch the unit toggle above and the calculator does it for you.
Scr is serum creatinine, the denominator of the Cockcroft-Gault equation: CrCl = [(140 − age) × weight] / (72 × Scr). Because Scr sits in the denominator, small changes at low creatinine values produce large changes in estimated clearance — the relationship is curvilinear, not linear.
The Cockcroft-Gault equation is CrCl (mL/min) = [(140 − age) × weight(kg)] / (72 × Scr in mg/dL), × 0.85 if female. In SI units it is [(140 − age) × weight(kg) × 1.23] / Scr in µmol/L for males, and × 1.04 for females. Published in Nephron, 1976.
Enter your age, sex, weight and most recent serum creatinine into the calculator above and the result appears immediately. Note that Cockcroft-Gault was designed for clinician use in drug dosing, not for self-assessment — discuss any result with a healthcare professional before acting on it.
Subtract age from 140, multiply by body weight in kilograms, divide by 72 times serum creatinine in mg/dL, then multiply by 0.85 for females. Choose the weight basis before you start: actual weight if below ideal, ideal weight at normal BMI, adjusted weight if BMI is 30 or above.
Use actual body weight if the patient weighs less than their ideal body weight, ideal body weight at a normal BMI, and adjusted body weight (IBW + 0.4 × [actual − IBW]) when BMI is 30 or above. This is convention rather than a validated equation, and institutional protocol takes precedence.
Yes — CLcr and CrCl are two abbreviations for the same quantity, creatinine clearance. CLcr follows the pharmacokinetic convention of writing clearance as CL with the cleared substance subscripted, and is the form used through most dosing literature; CrCl is the more common clinical shorthand. Cr-Cl, Cr Cl and C-cr appear too, and the equation itself is often shortened to CG. All of them mean the volume of plasma cleared of creatinine per minute, and all are calculated the same way — this calculator applies Cockcroft-Gault, as published in 1976.
A CrCl of 90 mL/min or above is treated as normal in the dosing-reference bands on this site, and 60 to 89 mL/min as mildly decreased. Normal is age-dependent: clearance falls by roughly 1 mL/min per year from about age 40, so the same figure can be unremarkable in an older patient and low in a younger one. These bands derive from KDIGO categories, which are defined on eGFR rather than CrCl — a dosing reference here, not a diagnosis.
Creatinine clearance is reported in mL/min and is not indexed to body size. eGFR is reported in mL/min/1.73 m², indexed to a standard body surface area, which is why the two cannot be compared directly without converting. For infusion and renal-replacement calculations mL/hour is sometimes needed — multiply mL/min by 60. Serum creatinine itself is reported in mg/dL or µmol/L, where 1 mg/dL = 88.4 µmol/L.
Security & privacy
All calculations run entirely in your browser. No patient values are transmitted, logged or stored.
The equations run as JavaScript on your device. There is no API endpoint that accepts a clinical value, because the calculation code never makes a network request.
Values are not written to a database, a log, local storage or a cookie. Closing the tab discards them.
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Message on WhatsAppAbout Ali Raza →Enter age, weight and serum creatinine into the CrCl calculator — the result appears as you type, with all three weight bases and the working shown in full.
Medical disclaimer: This calculator is intended for healthcare professional reference and educational purposes only. It does not replace clinical judgment or the advice of a licensed provider. Always verify dosing decisions against institutional protocol and current prescribing information.
