Creatinine Clearance (Cockcroft-Gault) Calculator
Estimate creatinine clearance the way DOAC trials did — Cockcroft-Gault with actual body weight — and see the label-based dose adjustment for each agent at the calculated clearance.
Reviewed by Zaka Ahmed, MD Clinical reference · 5 min read
Creatinine Clearance (Cockcroft-Gault)
Enter the values as measured. The DOAC trials (RE-LY, ROCKET AF, ARISTOTLE, ENGAGE AF) enrolled and dosed by Cockcroft-Gault using actual body weight — not by eGFR from the lab report, which can disagree by a full dosing tier.
Creatinine clearance appears here with the CKD-style stage and each DOAC's label-based dose at that clearance.
DOAC dosing at this clearance (US labels, nonvalvular AF)
Educational tool only. Dose selection must incorporate the full label, interactions, hepatic function, indication (AF doses shown — VTE dosing differs), and clinical judgment. Apixaban's renal criterion uses serum creatinine within its 2-of-3 rule, not clearance alone. Always verify against the current prescribing information.
Clinical notes & interpretation Scoring guidance, pitfalls, FAQs, and references
Why Cockcroft-Gault, not the lab's eGFR
Every pivotal DOAC trial screened and dosed patients by Cockcroft-Gault creatinine clearance calculated with actual body weight. The eGFR printed on the chemistry panel (CKD-EPI, normalized to 1.73 m²) tracks kidney disease well but was never the dosing variable — and in older, low-body-weight patients the two can differ enough to change a dabigatran or edoxaban tier. When a dosing decision sits near a threshold, calculate Cockcroft-Gault deliberately rather than reading eGFR off the report.
Where this matters most in stroke practice
Three recurring moments: choosing the DOAC dose after an AF-associated ischemic stroke, deciding whether a patient's admission "reduced-dose apixaban" was actually appropriate (underdosing without meeting criteria is common and associated with more strokes without less bleeding), and screening renal function before contrast studies and repeat CTA. Reversal-agent selection and redosing timelines after thrombolysis also lean on clearance. Note that apixaban is the exception in this panel: its reduction rule uses serum creatinine within the 2-of-3 criteria (age ≥80, weight ≤60 kg, SCr ≥1.5 mg/dL) rather than a clearance cutoff.
Limits of the estimate
Cockcroft-Gault assumes stable creatinine — it is not valid in AKI, where clearance is changing faster than creatinine reflects. It loses accuracy at the extremes of body composition (sarcopenia inflates clearance; obesity can overestimate it — some pharmacists substitute adjusted body weight above ~120% of ideal). In amputation, paralysis, or severe cachexia, creatinine-based equations overestimate function; consider cystatin C or measured clearance when the decision is consequential.
Frequently asked questions.
Should I use actual, ideal, or adjusted body weight?
The DOAC trials used actual body weight, so for DOAC dosing use actual body weight. In marked obesity Cockcroft-Gault can overestimate clearance; some institutions use adjusted body weight above roughly 120% of ideal for other drug dosing, but for DOACs the trial convention is the defensible default.
Why does my patient's eGFR say 55 but this calculator says 38?
Different equations answering different questions. eGFR is indexed to 1.73 m² of body surface area and calibrated for CKD staging; Cockcroft-Gault returns absolute clearance in mL/min for the person in front of you. Small, elderly patients commonly show exactly this pattern — and it is the Cockcroft-Gault number that the DOAC labels reference.
Can I use this in acute kidney injury?
No. All creatinine-based estimates assume steady state. In AKI, treat the number as unreliable and dose with pharmacy input based on trajectory, urine output, and the specific drug's kinetics.
Which DOAC is preferred in severe renal impairment?
Evidence thins below a clearance of 25–30 mL/min because the pivotal trials excluded those patients. Apixaban has the most observational support in advanced CKD and is commonly chosen, but this is a specialist, individualized decision — not one to settle from a calculator.
References.
- Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31–41. PubMed
- Steffel J, Collins R, Antz M, et al. 2021 EHRA practical guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation. Europace. 2021;23(10):1612–1676. PubMed
- Granger CB, Alexander JH, McMurray JJ, et al. Apixaban versus warfarin in patients with atrial fibrillation (ARISTOTLE). N Engl J Med. 2011;365(11):981–992. PubMed
- Giugliano RP, Ruff CT, Braunwald E, et al. Edoxaban versus warfarin in patients with atrial fibrillation (ENGAGE AF-TIMI 48). N Engl J Med. 2013;369(22):2093–2104. PubMed