Kidney function education
CKD Stage Calculator: KDIGO G1–G5
Map an adult laboratory eGFR to its KDIGO filtration category while distinguishing a numerical category from a CKD diagnosis.
CKD generally requires abnormalities lasting at least three months. G1 or G2 alone does not diagnose CKD. A single result below 60 may reflect acute kidney injury or a temporary change and requires clinical interpretation.
Method and equation
The category boundaries are G1 ≥90, G2 60–<90, G3a 45–<60, G3b 30–<45, G4 15–<30 and G5 <15 mL/min/1.73 m². Decimal values are compared before any rounding. KDIGO classifies CKD using its cause, GFR category and albuminuria category together, rather than the G category alone.
How to use this tool
- Enter the indexed adult laboratory eGFR, not Cockcroft–Gault creatinine clearance or an unindexed clearance. Check how long the abnormal finding has been present and whether urine albumin or another marker of kidney damage is abnormal.
- Review the original report, earlier results and relevant urine tests with a qualified clinician before making a care decision.
Worked example
An eGFR of 58 maps to G3a. Exactly 15 maps to G4, while 14.9 maps to G5. An eGFR of 75 maps to G2 but does not establish CKD without persistent kidney-damage evidence.
Understanding the result
CKD generally requires abnormalities lasting at least three months. G1 or G2 alone does not diagnose CKD. A single result below 60 may reflect acute kidney injury or a temporary change and requires clinical interpretation.
Limitations and safety
- The category cannot identify the cause, establish chronicity or determine treatment. Very low or rapidly falling results, particularly with symptoms, need prompt professional assessment. Pediatric results require pediatric interpretation.
- Educational use only. A result cannot diagnose disease or choose a medicine dose. Do not delay urgent care for symptoms or rapidly changing kidney results.
Sources
Method and explanations checked against the sources below on October 14, 2026. This is editorial and technical verification, not a physician review. External sources may be in English.