Choose the renal estimate explicitly required by the medicine reference, protocol or clinical source you are following. Keep the method name and units attached to the result.
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The two renal calculators stay separate because eGFR and Cockcroft-Gault CrCl are not interchangeable names for the same calculation.
CKD-EPI 2021
Calculate adult CKD-EPI 2021 eGFR from creatinine, with optional cystatin C and BSA adjustment where the workflow requires it.
Use when: The source asks for eGFR, CKD-EPI, or a value in mL/min/1.73 m².
Calculate eGFRCockcroft-Gault
Calculate adult Cockcroft-Gault creatinine clearance using age, serum creatinine and the body-weight method required by the current source.
Use when: The source explicitly asks for CrCl or Cockcroft-Gault in mL/min.
Calculate CrClSupporting calculation
Use the Dosing Body Measures hub only after the governing source has told you which body-weight method is required.
Choose the renal estimate named by your source
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Safety & checking
A renal method-selection error can matter more than the arithmetic. Verify the named equation, required weight input, creatinine units and result units before using the value.
1.Treating eGFR and CrCl as the same value
They are different estimates built from different equations. Match the method and units to the current source rather than swapping one number for the other.
2.Ignoring indexed versus absolute units
Laboratory eGFR is commonly reported as mL/min/1.73 m², while Cockcroft-Gault CrCl is reported as mL/min. The unit is part of the answer.
3.Letting the calculator choose a CrCl weight
Actual, ideal and adjusted body weight can change Cockcroft-Gault CrCl. Use the body-weight method specified by the governing source.
4.Over-trusting one creatinine result
Creatinine-based estimates can be less reliable when renal function is changing rapidly or creatinine does not reflect filtration well. Review the clinical context and trend.
Related
Quick answers for choosing eGFR or creatinine clearance and keeping the result in context.
Use the renal estimate and units specified by the current medicine reference, product information, pharmacist, prescriber instruction, or local protocol.
They are different estimating equations and handle body size differently, so their numerical results are not expected to match exactly.
No. De-indexing eGFR can express an eGFR-based estimate in mL/min, but it does not turn CKD-EPI into Cockcroft-Gault creatinine clearance.
No. MedMaths calculates the selected renal estimate; it does not choose a medicine, dose, interval, contraindication threshold, or dialysis adjustment.
Confirm age, serum-creatinine unit, sex factor, and the body-weight method required by the source before calculating.
The equations used in these calculators were developed by published researchers. These researchers are not affiliated with MedMaths and have not reviewed or endorsed this site.
Cockcroft-Gault Equation
Formula originally described by: Donald W. Cockcroft and M. Henry Gault
CKD-EPI 2021 Creatinine and Creatinine-Cystatin C Equations — CKD-EPI Collaboration
Based on research published by: Lesley A. Inker and Andrew S. Levey
Primary equation papers and current kidney-function guidance supporting the distinction between CKD-EPI eGFR and Cockcroft-Gault CrCl.
Cockcroft & Gault, Nephron (1976)
Original publication of the Cockcroft-Gault creatinine-clearance equation.
New England Journal of Medicine (2021)
Primary 2021 CKD-EPI publication for the contemporary race-free adult eGFR equations.
NIDDK
Clinical guidance on kidney-function estimates, body-size indexing and medication-dosing decisions.
KDIGO
Current international guidance for evaluation and management of chronic kidney disease, including GFR assessment.
