How to use it
- Choose the sex the equations use, then enter age and serum creatinine (switch between mg/dL and µmol/L).
- Enter weight for Cockcroft–Gault, and height if you want the ideal and adjusted body weight versions.
- Read eGFR and the three creatinine clearance figures, and check the working underneath.
Formulas
CKD-EPI 2021 (creatinine, without race): eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 [if female], with κ = 0.7 (female) or 0.9 (male) and α = −0.241 (female) or −0.302 (male). Scr is in mg/dL and the result in mL/min/1.73 m².
Cockcroft–Gault: CrCl = (140 − age) × weight (kg) ÷ (72 × Scr) × 0.85 [if female], in mL/min. Ideal body weight (Devine): 50 kg (men) or 45.5 kg (women) + 2.3 kg per inch over 5 feet. Adjusted body weight: IBW + 0.4 × (actual weight − IBW).
Worked example
A man of 60 with serum creatinine 1.2 mg/dL (106 µmol/L), 80 kg and 175 cm: CKD-EPI 2021 gives 142 × (1.2 ÷ 0.9)^−1.200 × 0.9938^60 = 69 mL/min/1.73 m². Cockcroft–Gault gives (140 − 60) × 80 ÷ (72 × 1.2) = 74.1 mL/min with actual weight. His ideal body weight is 70.5 kg and his adjusted weight 74.3 kg, giving 65.2 and 68.8 mL/min. For a woman with the same numbers the figures are 52 mL/min/1.73 m² and 63 mL/min.
KDIGO GFR categories (for reference)
| Category | GFR (mL/min/1.73 m²) | Term |
|---|---|---|
| G1 | 90 or more | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | Under 15 | Kidney failure |
KDIGO 2024 notes that without evidence of kidney damage, neither G1 nor G2 meets the criteria for chronic kidney disease; a category describes a number, not a diagnosis.
References
- Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–1749 (PMID 34554658). Equation as published by the National Kidney Foundation and NIDDK.
- Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31–41 (PMID 1244564).
- Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother 2000;34:1066–1069 (PMID 10981254).
- Winter MA, Guhr KN, Berg GM. Impact of various body weights and serum creatinine concentrations on the bias and accuracy of the Cockcroft-Gault equation. Pharmacotherapy 2012;32:604–612 (PMID 22576791).
- US FDA. Pharmacokinetics in Patients with Impaired Renal Function: Study Design, Data Analysis, and Impact on Dosing. Guidance for industry, 2024.
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024;105(4S):S117–S314, Table 2.
Formulas checked on 7 October 2026. For professionals: verify against current guidelines; this is not medical advice or a dosing tool.