E-GFR Calculator
eGFR Calculator
Calculate estimated kidney function using the MDRD and 2021 CKD-EPI equations.
eGFR Calculator – Estimate Kidney Function
The eGFR Calculator is a useful tool for estimating kidney filtration function using a person's age, sex and serum creatinine level. Estimated glomerular filtration rate, commonly known as eGFR, is widely used to assess kidney function in adults.
This calculator uses the MDRD equation as the primary calculation method and also provides an estimated GFR using the 2021 CKD-EPI creatinine equation for comparison.
Serum creatinine can be entered in either mg/dL or µmol/L. If µmol/L is selected, the calculator automatically converts the creatinine value into mg/dL before performing the calculation.
The estimated GFR is reported in mL/min/1.73 m². The result can be used to identify the commonly used GFR categories G1 through G5.
How to Use the eGFR Calculator
- Enter the patient's age in years.
- Select the patient's sex.
- Enter the serum creatinine value.
- Select the creatinine unit: mg/dL or µmol/L.
- Click the Calculate eGFR button.
- The calculator will display the primary MDRD eGFR, CKD-EPI eGFR and kidney function category.
This calculator is designed for adults aged 18 years or older.
MDRD eGFR Formula
The MDRD (Modification of Diet in Renal Disease) equation is a commonly used equation for estimating glomerular filtration rate from serum creatinine, age and sex.
Where:
- SCr = serum creatinine in mg/dL
- Age = age in years
- 0.742 = female factor
The historical race coefficient is not included in this calculator.
2021 CKD-EPI Creatinine Equation
The calculator also provides an estimated GFR using the 2021 CKD-EPI creatinine equation.
Where:
- SCr = 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
The result is expressed as mL/min/1.73 m².
eGFR Kidney Function Categories
| GFR Category | eGFR Range | Description |
|---|---|---|
| G1 | ≥ 90 mL/min/1.73 m² | Normal or high |
| G2 | 60–89 mL/min/1.73 m² | Mildly decreased |
| G3a | 45–59 mL/min/1.73 m² | Mildly to moderately decreased |
| G3b | 30–44 mL/min/1.73 m² | Moderately to severely decreased |
| G4 | 15–29 mL/min/1.73 m² | Severely decreased |
| G5 | < 15 mL/min/1.73 m² | Kidney failure range |
GFR categories should be interpreted together with other markers of kidney damage and the patient's clinical condition.
Serum Creatinine Unit Conversion
Serum creatinine may be reported in mg/dL or µmol/L depending on the laboratory. The calculator automatically converts µmol/L into mg/dL before calculating eGFR.
For example, 88.4 µmol/L creatinine is approximately equal to 1.00 mg/dL.
Important Information About eGFR
eGFR is an estimated value rather than a direct measurement of glomerular filtration rate. Its accuracy may be affected by factors such as unusual muscle mass, diet, certain medical conditions and changes in serum creatinine.
A low eGFR does not automatically mean that a person has chronic kidney disease. Chronic kidney disease is generally assessed using persistent abnormalities in kidney function or evidence of kidney damage over time.
Urine albumin-to-creatinine ratio (UACR), blood pressure, medical history, medications and other laboratory findings may also be important when evaluating kidney health.
Frequently Asked Questions
Medical Disclaimer
This eGFR calculator is provided for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Do not make medical decisions based solely on this calculator. Always discuss abnormal kidney function results with a qualified healthcare professional.