eGFR Calculator (CKD-EPI 2021 Creatinine Equation) with CKD Stage
Estimate your glomerular filtration rate from serum creatinine with the 2021 CKD-EPI equation, the current standard, and see the matching CKD stage.
✓ Formulas cited from the published literature
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About this calculator
The estimated glomerular filtration rate (eGFR) is the standard way to judge kidney function and to stage chronic kidney disease. The 2021 CKD-EPI equation removed the race coefficient used in earlier versions and is now recommended by the National Kidney Foundation and American Society of Nephrology.
Enter your serum creatinine, age and sex to calculate eGFR. Values in mg/dL or µmol/L are both supported.
How it works
eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938age × 1.012 [if female]
κ = 0.7 (women) or 0.9 (men); α = −0.241 (women) or −0.302 (men); Scr in mg/dL. Result in mL/min/1.73 m².
How to read your result
| Category | eGFR | Meaning |
|---|---|---|
| G1 | ≥ 90 | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mild to moderately decreased |
| G3b | 30–44 | Moderate to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | < 15 | Kidney failure |
G1 and G2 only count as CKD if there is other evidence of kidney damage, such as albuminuria. Use the UACR calculator for that part of staging.
Worked example
A 55-year-old woman with serum creatinine 1.1 mg/dL.
| eGFR (CKD-EPI 2021) | 59 mL/min/1.73 m² |
| GFR category (KDIGO) | G3a Mildly to moderately decreased |
Frequently asked questions
What is a normal eGFR?
An eGFR of 90 or above is considered normal for young adults. GFR falls with age, so mildly lower values in older people may be normal for age.
What is the CKD-EPI 2021 equation?
It is the latest creatinine-based equation from the CKD-EPI collaboration, developed without a race variable.
eGFR vs creatinine clearance: what is the difference?
eGFR is normalised to body surface area (1.73 m²) and is used to stage CKD. Creatinine clearance (Cockcroft-Gault) is in mL/min and is used in drug labelling.
Can eGFR change day to day?
Yes. Hydration, a cooked-meat meal, intense exercise and illness can cause small shifts. Diagnosis requires results persisting for at least 3 months.
When is eGFR unreliable?
In acute kidney injury, extremes of body size or muscle mass, pregnancy, and with some drugs that block creatinine secretion. Cystatin C can help in those cases.
Limitations and when not to use
For adults 18+ only (children use bedside Schwartz). Not valid in acute kidney injury. Does not replace evaluation by a clinician.
Sources and references
Last updated: 2026-10-09