UKMedCalc

For healthcare professionals. Educational tool only — not a medical device. Verify all results against the current BNF, NICE guidance and local policy, and apply clinical judgement.

RenalPharmacy

Creatinine Clearance (Cockcroft–Gault)

Estimates creatinine clearance for drug dosing from age, sex, weight and serum creatinine, with actual, ideal or adjusted body weight options.

years

The original equations were derived using sex at birth

kg
cm

Only used when ideal or adjusted body weight is selected

Steady-state value only — eGFR is unreliable in acute kidney injury

Adjusted weight = IBW + 0.4 × (actual − IBW); common when actual weight exceeds ~120–130% of IBW. Follow local policy.

Enter the required values to see the result.

Formula

CrCl (mL/min)=(140−age)×weight (kg)72×SCr  (mg/dL)×0.85  (if female)\text{CrCl (mL/min)} = \frac{(140 - \text{age}) \times \text{weight (kg)}}{72 \times S_{Cr} \; (\text{mg/dL})} \times 0.85 \; \text{(if female)}

Serum creatinine must be in mg/dL (divide µmol/L by 88.4 — handled automatically). Weight may be actual, ideal (Devine) or adjusted body weight depending on body habitus and local policy.

Caveats & limitations

  • Requires stable renal function; unreliable in acute kidney injury.
  • Inaccurate at extremes of muscle mass (cachexia, amputation, bodybuilding), in severe liver disease, and with drugs that block creatinine secretion (e.g. trimethoprim).
  • For CKD diagnosis and staging, eGFR equations (CKD-EPI) are preferred — see NICE NG203.
  • Not indexed to body surface area, unlike eGFR equations.

Evidence & UK guidance

Primary evidence

  • Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31–41.

    PubMed

UK practice

Still widely used in UK practice for drug dosing: the BNF and many Summaries of Product Characteristics express renal dose adjustments in terms of Cockcroft–Gault creatinine clearance rather than eGFR. The choice of weight (actual, ideal or adjusted) materially changes the result in obesity — follow local policy.

Official resources

Formula and citations last verified: 2026-08-03

Related calculators

CKD-EPI 2021 eGFR

Estimates GFR using the 2021 CKD-EPI creatinine equation, refitted without a race coefficient (ASN/NKF recommendation in the US).

CKD-EPI 2009 eGFR

Estimates GFR using the original 2009 CKD-EPI creatinine equation — the basis of eGFR reported by UK laboratories.

MDRD eGFR

Estimates GFR using the 4-variable MDRD Study equation re-expressed for standardised (IDMS-traceable) creatinine. Largely superseded by CKD-EPI.

IBW / AdjBW

Calculates Devine ideal body weight and, when actual weight is provided, adjusted body weight for dosing in obesity.