Estimated glomerular filtration rate (eGFR) approximates how much blood the kidneys filter per minute (mL/min/1.73 m²). It is the primary measure for chronic kidney disease (CKD) detection and staging per KDIGO guidelines.

Which eGFR formula should I use?

The 2021 CKD-EPI race-free creatinine equation is currently recommended in the U.S. as the first-line formula. If cystatin C is available, the combined CKD-EPI 2021 creatinine + cystatin C equation is the most accurate. For children and adolescents, use the Bedside Schwartz 2009 formula.

What eGFR value defines CKD?

CKD is defined as eGFR < 60 mL/min/1.73 m² persisting for ≥ 3 months, or markers of kidney damage (albuminuria, abnormal imaging, structural abnormalities) regardless of eGFR. KDIGO classifies CKD by G1–G5 stage and A1–A3 albuminuria.

Why did CKD-EPI 2021 remove the race coefficient?

The 2009 CKD-EPI and MDRD equations included a race coefficient that overestimated eGFR in Black patients, potentially delaying specialist referral. The 2021 CKD-EPI equation was refit without race, reducing bias while maintaining accuracy. All major U.S. laboratories have transitioned to the 2021 formula.

🩺 eGFR Calculator

Compare 9 formulas using creatinine and cystatin C. Adults + pediatrics.

For reference only — Educational use. Not a substitute for clinical judgment.

Adult (≥ 18 yr)

Pediatric / Adolescent

Age (years)

Sex

Serum Creatinine (mg/dL)

Required

Cystatin C (mg/L)

Optional — enables CysC-based formulas

Height (cm)

Required for Schwartz formulas

Pediatric Subtype

Weight (kg) [optional]

Needed for Cockcroft-Gault

Creatinine Assay

KDIGO CKD Staging

G1 ≥ 90 (normal or high) G2 60–89 (mildly decreased) G3a 45–59 (mild-to-moderate) G3b 30–44 (moderate-to-severe) G4 15–29 (severe) G5 < 15 (kidney failure)

Related Calculators

🔬 ACR (CKD Albuminuria Staging) 🧫 Urine Protein/Creatinine Ratio 📊 HbA1c Calculator

What is eGFR?

Estimated glomerular filtration rate (eGFR) approximates the volume of blood filtered by the kidneys per minute, normalized to 1.73 m² of body surface area (mL/min/1.73 m²). It is the single most important measure for detecting, staging, and monitoring chronic kidney disease (CKD).

KDIGO (Kidney Disease: Improving Global Outcomes) recommends classifying CKD using eGFR (G1–G5) together with albuminuria (A1–A3). Neither measure alone is sufficient.

✅ Action Guide by CKD Stage

G1 eGFR ≥ 90

Normal kidney function. Annual screening is sufficient in the absence of risk factors. Maintain healthy lifestyle and control cardiovascular risk factors.

G2 eGFR 60–89

Mildly decreased. Without albuminuria or structural disease, this alone does not define CKD. Repeat testing every 6–12 months. Address hypertension, diabetes, and nephrotoxic exposure.

G3a eGFR 45–59

Nephrology referral is appropriate, especially with albuminuria or rapid progression. Initiate ACE inhibitor or ARB if proteinuria. Avoid NSAIDs. Recheck every 3–6 months. Review medication doses for renal adjustment.

G3b eGFR 30–44

Nephrology follow-up is essential. Screen for CKD complications: anemia (Hgb, iron studies), CKD-MBD (calcium, phosphate, PTH, vitamin D), and acidosis (bicarbonate). SGLT2 inhibitor recommended in diabetic and proteinuric CKD. Recheck every 3 months.

G4 eGFR 15–29

Prepare for renal replacement therapy. Discuss hemodialysis, peritoneal dialysis, transplant, and conservative management options. Vascular access planning (AV fistula) should begin. Restrict dietary potassium and phosphate as indicated.

G5 eGFR < 15

Kidney failure. Dialysis or transplantation is typically required unless conservative management has been chosen. Watch for emergencies: hyperkalemia, volume overload, uremic encephalopathy, pericarditis.

🔗 Next Steps

→ Check urine ACR — CKD classification requires both eGFR and albuminuria
→ HbA1c — diabetes is the leading cause of CKD worldwide
→ Blood pressure — hypertension is the second leading cause
→ LDL cholesterol — statin therapy reduces cardiovascular risk in most CKD patients

Disclaimer — This calculator is for educational and reference purposes only. Reference ranges and formula choice may vary by laboratory, assay, and clinical setting. Clinical decisions must be based on the patient's complete medical context, not isolated eGFR values. This tool does not replace professional medical judgment.
References: Inker LA et al. NEJM 2021 (CKD-EPI 2021) · Pottel H et al. Ann Intern Med 2021 (EKFC) · Schwartz GJ et al. JASN 2009 (Bedside Schwartz) · Levey AS et al. Ann Intern Med 2009 (CKD-EPI 2009) · KDIGO 2024 CKD Clinical Practice Guideline.