eGFR Calculator – CKD-EPI 2021
Calculate estimated glomerular filtration rate (eGFR) using the 2021 CKD-EPI creatinine equation. Enter age, sex, and serum creatinine in mg/dL or µmol/L.
CKD-EPI 2021 eGFR Calculator
Read the complete LabProSuite guide covering the CKD-EPI 2021 formula, eGFR normal range, calculation example, creatinine, cystatin C, clinical interpretation, and limitations.
Read the Complete eGFR Guide →This calculator is designed for educational and laboratory reference purposes. It uses the 2021 CKD-EPI creatinine equation for adults and does not include race as a calculation variable.
What Is eGFR?
Estimated glomerular filtration rate (eGFR) is a calculated estimate of kidney filtration function. It is commonly reported in mL/min/1.73 m².
eGFR is not a direct measurement of GFR. Instead, it is estimated using mathematical equations based on filtration markers and demographic variables.
What Is the CKD-EPI 2021 Equation?
The CKD-EPI 2021 creatinine equation estimates GFR using standardized serum creatinine, age, and sex.
Unlike older equations that included a race coefficient, the 2021 CKD-EPI creatinine equation does not use race as a variable.
CKD-EPI 2021 Creatinine Formula
Where:
- Scr = standardized serum creatinine in mg/dL
- κ = 0.7 for females and 0.9 for males
- α = −0.241 for females and −0.302 for males
- Age = age in years
- min = minimum of Scr/κ or 1
- max = maximum of Scr/κ or 1
Creatinine Conversion: mg/dL and µmol/L
The calculator automatically converts creatinine entered in µmol/L to mg/dL before applying the conventional-unit CKD-EPI 2021 equation.
eGFR Categories
| Category | eGFR (mL/min/1.73 m²) | Description |
|---|---|---|
| G1 | ≥90 | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | <15 | Kidney failure |
How Should eGFR Be Interpreted?
eGFR should not be interpreted as an isolated number. Chronic kidney disease assessment considers the duration of abnormal kidney findings, urine albumin, clinical history, and other laboratory information.
An eGFR between 60 and 89 mL/min/1.73 m² does not by itself establish chronic kidney disease when there are no other markers of kidney damage.
Limitations of eGFR
- eGFR is an estimate rather than a direct measurement of GFR.
- Creatinine is affected by muscle mass and other non-kidney factors.
- Rapidly changing kidney function can make creatinine-based estimates less reliable.
- Extreme body composition can affect creatinine-based eGFR.
- Appropriate creatinine assay standardization is important.
Frequently Asked Questions
What formula does this calculator use?
This calculator uses the 2021 CKD-EPI creatinine equation for adults.
Does CKD-EPI 2021 use race?
No. The 2021 CKD-EPI creatinine equation does not include race as a variable.
What creatinine units can I enter?
You can enter serum creatinine in mg/dL or µmol/L.
What is a normal eGFR?
An eGFR of 90 mL/min/1.73 m² or higher is classified as G1, normal or high. Other evidence of kidney health should also be considered.
Is an eGFR of 60–89 kidney disease?
Not necessarily. G2 is classified as mildly decreased, but an eGFR of 60–89 alone does not establish CKD without other qualifying evidence of kidney damage.
Can one eGFR result diagnose CKD?
No. CKD requires persistent abnormalities for at least 3 months or other qualifying evidence of kidney damage.
Is eGFR the same as creatinine clearance?
No. eGFR and creatinine clearance are different estimates and use different calculation methods and units.
Disclaimer
This calculator is provided for educational and laboratory reference purposes only. eGFR is an estimated value and should not be used as the sole basis for diagnosis, treatment, or medication dosing decisions.
Clinical interpretation should be performed by a qualified healthcare professional using the complete clinical picture, laboratory findings, applicable guidelines, and institutional protocols.
