Creatinine clearance (Cockcroft-Gault)

The Cockcroft-Gault formula estimates creatinine clearance in ml/min from serum creatinine, age and body weight. Unlike the eGFR, the result is not normalised to 1.73 m² body surface area.

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Calculator

Unit
years
kg
Sex
–ml/min

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Formula

Creatinine clearance (ml/min) = (140 − age) × body weight (kg) ÷ (72 × serum creatinine in mg/dl), × 0.85 in women. Serum creatinine in µmol/l is divided by 88.4. Cockcroft and Gault derived the formula in 1976 from 249 patients (mostly men) aged 18 to 92 years; for women they proposed a value 15% lower.

Cockcroft-Gault and eGFR

The Cockcroft-Gault formula estimates creatinine clearance in ml/min, the CKD-EPI equation glomerular filtration rate in ml/min/1.73 m². The two values are not interchangeable. The KDIGO categories G1–G5 refer to GFR and are therefore not shown here.

Limitations

The formula uses actual body weight; in obesity, oedema or low muscle mass the estimate deviates markedly. Variants using ideal or adjusted body weight exist but are not implemented here. Creatinine was measured in 1976 with older laboratory methods that differ from today’s standardised methods. Any creatinine-based estimate is unreliable when kidney function is unstable.

FAQ

Why is Cockcroft-Gault clearance not normalised to 1.73 m²?▾

The formula includes body weight directly and estimates the individual’s absolute creatinine clearance in ml/min. The CKD-EPI eGFR, by contrast, refers to a standard body surface area.

Why the factor 0.85 in women?▾

The formula was derived in men. Cockcroft and Gault proposed a 15% lower value for women because of their lower average muscle mass.

References

  1. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31–41. · PubMed
  2. Inker LA et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med 2021;385:1737–49. · PubMed

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Intended purpose: learning tool for medical education only. Not intended for use in patients or for diagnostic or treatment decisions; not a medical device. Calculations follow the cited original publications; no guarantee of completeness or correctness. Last updated: 10/2026 · Dr. Pascal Bafteh