GFR Calculator

years
mg/dL

About the GFR Calculator

Estimated Glomerular Filtration Rate (eGFR) is a key measure of how well your kidneys are filtering waste from your blood, commonly used to screen for kidney disease.

Formula Used

eGFR = 175 × (Scr)^-1.154 × (Age)^-0.203 × (0.742 if female)

How It Works

This calculator uses the MDRD (Modification of Diet in Renal Disease) formula, which estimates GFR from your serum creatinine level, age, and gender.

Step by Step

  1. Enter your serum creatinine level in mg/dL from a blood test.
  2. Enter your age and select your gender.
  3. The MDRD formula combines these to estimate your kidney filtration rate.

Worked Example

Example: A 45-year-old man with creatinine 1.0 mg/dL:

eGFR = 175 × (1.0)^-1.154 × (45)^-0.203 ≈ 81 mL/min/1.73m²

Reference Table

eGFR RangeStage
90+Normal (Stage 1)
60-89Mildly reduced (Stage 2)
30-59Moderately reduced (Stage 3)
15-29Severely reduced (Stage 4)
Below 15Kidney failure (Stage 5)

Frequently Asked Questions

What is a normal GFR value?

A GFR of 90 or above is generally considered normal, while values below 60 for three months or more may indicate chronic kidney disease.

Is this a substitute for a doctor's diagnosis?

No, this is an estimate for general awareness only - always consult a doctor for proper kidney function testing and diagnosis.

Why does gender affect the GFR formula?

Men typically have more muscle mass, which affects baseline creatinine levels, so the formula includes a correction factor for women.