GFR Calculator
Calculate Glomerular Filtration Rate for kidney function assessment
GFR Calculator
The GFR (glomerular filtration rate) Calculator estimates GFR values based on factors including serum creatinine value, age, race, and gender. For comparison purposes, the results for three prevalent formulas used for estimating GFR are provided.
Quick Navigation
👨⚕️ GFR Calculator for Adults
This calculator is for people aged 18 years or older.
📊 Result
| Formula | Result |
|---|---|
| MDRD 4-Variable Equation | 89.3 mL/min/1.73 m² |
| CKD-EPI Formula | 99.2 mL/min/1.73 m² |
| Mayo Quadratic Formula | 120.3 mL/min/1.73 m² |
Chronic Kidney Disease Stages
| Stage | GFR Value (mL/min/1.73 m²) |
|---|---|
| Normal | 90+ or above and no proteinuria |
| CKD1 | 90+ with evidence of kidney damage |
| CKD2 (Mild) | 60 to 89 with evidence of kidney damage |
| CKD3 (Moderate) | 30 to 59 |
| CKD4 (Severe) | 15 to 29 |
| CKD5 Kidney failure | less than 15 |
👶 GFR Calculator for Children
This calculator is for people aged 18 years or younger.
Result
GFR Result will be displayed here after calculation.
📚 Understanding GFR
What is GFR?
Glomerular filtration rate describes the rate of flow of filtered fluids through the kidney and is used as a measure of kidney function. Generally, a higher value of GFR indicates better kidney function.
Normal GFR Ranges
The normal range of GFR adjusted for body surface area is 100 to 130 mL/min/1.73m² in men and 90 to 120mL/min/1.73m² in women below the age of 40. After age 40, GFR decreases progressively with age.
GFR Formulas
Multiple formulas are used to estimate GFR, including MDRD, CKD-EPI, and Mayo Quadratic. Each formula may give slightly different results, providing a range for clinical interpretation.
Population Mean Estimated GFR
| Age | Mean Estimated GFR (mL/min/1.73 m²) |
|---|---|
| 20-29 | 116 |
| 30-39 | 107 |
| 40-49 | 99 |
| 50-59 | 93 |
| 60-69 | 85 |
| 70+ | 75 |
Measuring GFR
The most accurate way to determine GFR involves the measurement of the rate at which an external substance such as inulin is removed from the bloodstream, termed inulin clearance. However, this method is impractical for routine clinical use, so many formulas have been developed to estimate GFR based on serum creatinine levels.
GFR Calculation Formulas
The IDMS-traceable MDRD study equation
GFR = 175 × (SCr)-1.154 × (age)-0.203 × (0.742 if female) × (1.212 if Black)
where SCr = serum creatinine in mg/dL
The CKD-EPI formula
This formula uses different equations based on gender, race, and creatinine level ranges.
The Mayo Quadratic Formula
GFR = e(1.911 + 5.249/SCr - 2.114/SCr2 - 0.00686 × age - (0.205 if female))
If SCr < 0.8 mg/dL, use 0.8 mg/dL for SCr
Estimated GFR for children using Schwartz formula
GFR = 0.413 × height(in cm) / SCr