GFR Calculator

Estimate Glomerular Filtration Rate (GFR) - a key measure of kidney function

⚠️ Important - For Healthcare Professionals Only This calculator is intended for use only by healthcare professionals. Patients should consult their healthcare provider for interpretation of results and medical advice. GFR estimates should not replace clinical judgment and must be interpreted in the context of the patient's overall clinical presentation.
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Adult GFR Calculator

Years (18+)

Note: Race-free CKD-EPI equation (2021) is now recommended by NKF/ASN

💡 Normal GFR: 100-130 mL/min/1.73m² for men under 40, 90-120 for women under 40. GFR decreases with age. Values ≥60 are generally adequate for most people.
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Estimated GFR
mL/min/1.73 m²
CKD Stage
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Kidney Function
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Classification
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CKD Stage Classification
Chronic Kidney Disease stages based on GFR value
Stage GFR (mL/min/1.73 m²) Description
Normal 90+ or above Normal kidney function, no proteinuria
CKD 1 90+ Normal/high GFR with evidence of kidney damage
CKD 2 (Mild) 60-89 Mildly decreased GFR with kidney damage
CKD 3 (Moderate) 30-59 Moderately decreased GFR
CKD 4 (Severe) 15-29 Severely decreased GFR
CKD 5 (Failure) <15 Kidney failure, dialysis may be needed
Normal GFR by Age
Age Range Mean Estimated GFR (mL/min/1.73 m²)
20-29116
30-39107
40-4999
50-5993
60-6985
70+75
Understanding Your GFR Results
What is GFR? Glomerular Filtration Rate (GFR) describes the flow rate of filtered fluids through the kidney. It is the best overall measure of kidney function. Generally, a higher GFR indicates better kidney function.
GFR Above 60 mL/min/1.73m² Usually adequate for most patients and alone is not necessarily indicative of chronic kidney disease (CKD). However, a significant decline from previous tests could indicate early kidney disease. Early diagnosis and treatment can prevent or delay the need for dialysis.
GFR Below 60 mL/min/1.73m² May indicate decreased kidney function. The lower the GFR, the more severely kidney function is impaired. Consult with a nephrologist for proper evaluation and management. CKD staging requires GFR measurements over ≥3 months.
⚠️ Medical Disclaimer and Important Information
  • For Healthcare Professionals Only: This calculator is designed for use by qualified healthcare professionals only. Patients should not use this tool for self-diagnosis.
  • Estimates Only: GFR values provided are estimates. Actual GFR can only be measured directly with specialized tests (e.g., inulin clearance).
  • Clinical Context Required: Results must be interpreted within the clinical context. GFR estimates have limitations and should be used alongside other clinical findings.
  • Race Considerations: The 2021 CKD-EPI equation (race-free) is now recommended by NKF/ASN Task Force. Older formulas included race adjustments which are no longer recommended.
  • Creatinine Limitations: Serum creatinine can be affected by muscle mass, diet, medications, and other factors. High muscle mass may elevate creatinine without indicating kidney disease.
  • Not for Diagnosis: This tool does not diagnose kidney disease. GFR <60 for <3 months or GFR ≥60 without evidence of kidney damage does not meet CKD criteria.
  • Consult Healthcare Provider: All results should be discussed with a qualified healthcare provider. Do not make treatment decisions based solely on this calculator.
  • Regular Monitoring: Kidney function should be monitored regularly, especially in patients with risk factors (diabetes, hypertension, family history).
  • Accuracy: While formulas are based on validated medical research, individual results may vary. Clinical judgment is essential.
  • Emergency Situations: If experiencing severe symptoms (decreased urination, swelling, confusion, chest pain), seek immediate medical attention.