GFR Calculator (Kidney Function)

Calculates estimated Glomerular Filtration Rate (eGFR) using the official 2021 CKD-EPI creatinine equation (race-free) and identifies Chronic Kidney Disease (CKD) stages G1 to G5.

Fitness & Clinical• 2021 CKD-EPI Creatinine Equation

GFR Calculator (Kidney Function)

Estimate Glomerular Filtration Rate (eGFR) and kidney disease stage from serum creatinine.

Gender

Age10 – 120 yrs

yrs

Serum Creatinine (mg/dL)0.2 – 15 mg/dL

mg/dL

KDIGO eGFR Renal StageG1: Normal (≥90)

104mL/min/1.73m²

G1: Normal (≥90)

G5: Failure (<15)

0-14.9

G4: Severe (15-29)

15-29.9

G3b: Moderate (30-44)

30-44.9

G3a: Mild-Mod (45-59)

45-59.9

G2: Mild (60-89)

60-89.9

G1: Normal (≥90)

90-120

Classification:Normal kidney function.

Evidence-based estimations. Consult a physician for personalized guidance.

Clinical Formula & Calculation Standard

Official clinical definitions and validated mathematical models

2021 CKD-EPI Creatinine Equation (Race-Free Standard)

eGFR = 142 × min(SCr/κ, 1)^α × max(SCr/κ, 1)^-1.200 × 0.9938^Age × (1.012 if female) (κ = 0.7 for female, 0.9 for male; α = -0.241 for female, -0.302 for male)

The 2021 CKD-EPI creatinine equation was established by the National Kidney Foundation and American Society of Nephrology task force to evaluate renal function without a race coefficient.

KDIGO Chronic Kidney Disease (CKD) Staging

Stage	eGFR (mL/min/1.73m²)	Functional Description	Recommended Clinical Action
Stage G1	≥ 90	Normal or high kidney filtration	Annual monitoring if proteinuria is present
Stage G2	60 – 89	Mildly decreased kidney function	Identify underlying cause, monitor risk factors
Stage G3a	45 – 59	Mild to moderately decreased	Evaluate complications, adjust nephrotoxic meds
Stage G3b	30 – 44	Moderately to severely decreased	Nephrology referral, metabolic bone monitoring
Stage G4	15 – 29	Severely decreased kidney function	Prepare for renal replacement therapy / transplant
Stage G5	< 15	Kidney failure / End-stage renal disease	Dialysis or kidney transplantation required

Clinical Insights & Practical Usage

Normal adult eGFR is typically above 90 mL/min/1.73m², declining physiologically with age by ~1 mL/min/year after age 40.
Serum creatinine can be elevated by high muscle mass, red meat ingestion, or creatine supplementation.

Medical Disclaimer: eGFR estimates kidney filtration rate and must be interpreted alongside urinalysis (albumin-to-creatinine ratio) by a physician.

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