GFR Calculator - Calculator See


GFR Calculator

Calculate estimated Glomerular Filtration Rate (eGFR) and Chronic Kidney Disease (CKD) staging using the race-free 2021 CKD-EPI creatinine equation.

Calculator Inputs

mg/dL
Blood laboratory creatinine value.
yrs
Patient age.
Sex-specific baseline constants.

Calculated Results

Estimated GFR (eGFR)
98 mL/min/1.73 m² (Normal)
Kidney Function Category Stage 1 (Normal or High Function)
Clinical Risk Tier Low Risk of Progression
Equation Used CKD-EPI Creatinine (2021 Refreshed)
Values calculate live as you adjust inputs.

About GFR Calculator

Glomerular Filtration Rate (GFR) measures how efficiently the kidney glomeruli filter waste products from blood, serving as the primary diagnostic benchmark for chronic kidney disease staging.

What is GFR Calculator?

Glomerular Filtration Rate (GFR) measures how efficiently the kidney glomeruli filter waste products from blood, serving as the primary diagnostic benchmark for chronic kidney disease staging.

How to Use This Calculator

  1. Enter blood serum creatinine (from your metabolic blood panel).
  2. Input patient age and biological sex.
  3. Review calculated filtration rate and corresponding CKD stage.

The Mathematical Formula & Variables

eGFR = 142 * min(Scr/kappa, 1)^alpha * max(Scr/kappa, 1)^-1.200 * 0.9938^Age * (1.012 if female)

Variables Definition

Symbol / Variable Name Description
>= 90 Stage 1 Normal kidney function.
60-89 Stage 2 Mildly decreased kidney function.
30-59 Stage 3 Moderate kidney dysfunction (Stage 3a and 3b).
< 15 Stage 5 Kidney failure requiring dialysis or transplant.

Step-by-Step Worked Example

Scenario: 45-year-old male with serum creatinine of 0.90 mg/dL.

  1. Scr/kappa = 0.90 / 0.90 = 1.00.
  2. Age factor = 0.9938^45 = 0.7561.
  3. eGFR = 142 * (1.0)^-0.302 * (1.0)^-1.200 * 0.7561 = 107.4 mL/min/1.73m².

Result: eGFR = 107 mL/min/1.73 m² (Normal)

Frequently Asked Questions

What is the updated 2021 race-free CKD-EPI guideline?

In 2021, the National Kidney Foundation (NKF) and American Society of Nephrology (ASN) eliminated race from eGFR calculations to promote equitable clinical diagnostics across all demographics.