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⚕️ Medical Calculator
eGFR Calculator (CKD-EPI)
Estimate glomerular filtration rate and stage chronic kidney disease using the CKD-EPI equation.
⚠️ For educational purposes only. Always consult a qualified healthcare professional before making clinical decisions.
✅ G1: Normal or high kidney function. Monitor if risk factors present.
✅ G2: Mildly decreased. Monitor annually.
⚠️ G3a: Mild to moderate decrease. Refer to GP for monitoring.
⚠️ G3b: Moderate to severe decrease. Nephrology referral recommended.
🔴 G4: Severely decreased. Nephrology referral needed urgently.
🚨 G5: Kidney failure. Renal replacement therapy planning required.
About This GFR / eGFR Calculator
This free eGFR (estimated Glomerular Filtration Rate) calculator estimates kidney function using the CKD-EPI equation — the most widely recommended formula in current clinical guidelines.
eGFR is the primary test used to assess kidney function and stage chronic kidney disease (CKD). It is calculated from serum creatinine, age, and sex using validated equations.
CKD Staging by eGFR
KDIGO CKD stages: G1 ≥90 Normal/High; G2 60-89 Mildly decreased; G3a 45-59 Mildly-moderately decreased; G3b 30-44 Moderately-severely decreased; G4 15-29 Severely decreased; G5 <15 Kidney failure. CKD staging requires persistent abnormalities for >3 months.
Frequently Asked Questions
Which eGFR equation should I use?+
CKD-EPI creatinine equation is recommended by most current guidelines (KDIGO, NKF). CKD-EPI creatinine-cystatin C may be more accurate when eGFR is 15-60. MDRD is no longer preferred.
How does eGFR differ from creatinine clearance?+
eGFR is estimated from serum creatinine using validated equations. Creatinine clearance is measured directly from a 24-hour urine collection — more labour-intensive but may be more accurate in certain populations.
What factors affect eGFR accuracy?+
Factors reducing eGFR accuracy: extremes of muscle mass (bodybuilders, amputees, malnourished), high meat intake, certain medications (trimethoprim, cimetidine), acute kidney injury, and pregnancy.
At what eGFR should nephrology referral be considered?+
KDIGO guidelines recommend referral when eGFR is <30 (G4-G5), or with rapidly declining eGFR (>5 ml/min/year), or with complications of CKD requiring specialist management.
Is this calculator suitable for paediatric patients?+
No — this calculator uses adult CKD-EPI equations. Paediatric eGFR requires different equations such as the Bedside Schwartz formula.