What is GFR and why is it important?

GFR (Glomerular Filtration Rate) is the best test to measure your level of kidney function and determine your stage of kidney disease. Your doctor can calculate it from the results of your blood creatinine test, your age, body size, and gender. A normal GFR is about 90-120 mL/min/1.73m².

How accurate is the GFR calculator?

This calculator uses the CKD-EPI formula, which is currently considered the most accurate method for estimating GFR. However, it provides an estimate and should not replace comprehensive medical evaluation. Actual kidney function assessment requires additional tests and clinical evaluation by a healthcare professional.

What do the different GFR stages mean?

Chronic Kidney Disease is classified into 5 stages based on GFR: Stage 1 (GFR >90) - Kidney damage with normal function; Stage 2 (GFR 60-89) - Mild loss; Stage 3 (GFR 30-59) - Moderate loss; Stage 4 (GFR 15-29) - Severe loss; Stage 5 (GFR <15) - Kidney failure requiring dialysis or transplant.

GFR Calculator - Estimate Kidney Function & Glomerular Filtration Rate

🩸 Serum Creatinine (mg/dL)

👤 Age (years)

🚻 Gender

🌍 Race

Your Estimated Kidney Function

0 mL/min/1.73m²

CKD Stage: Not determined

📋 Chronic Kidney Disease Stages

● Stage 1: GFR >90 - Normal kidney function
● Stage 2: GFR 60-89 - Mild loss
● Stage 3: GFR 30-59 - Moderate loss
● Stage 4: GFR 15-29 - Severe loss
● Stage 5: GFR <15 - Kidney failure

🏥 NKF & Medical Guidelines

💧 Stay well-hydrated with water throughout the day
🥗 Follow a kidney-friendly diet low in sodium and protein if recommended
💊 Monitor blood pressure and control it within target range
🩸 Manage blood sugar levels if you have diabetes
🚭 Avoid NSAIDs and other medications that can harm kidneys

Understanding GFR and Kidney Function

Glomerular Filtration Rate (GFR) is the best overall measure of kidney function. It represents the flow rate of filtered fluid through the kidneys and is calculated from your serum creatinine level, age, sex, and body size.

How GFR is Calculated

This calculator uses the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation, which is currently considered the most accurate method for estimating GFR. The formula accounts for:

Serum creatinine: A waste product from muscle metabolism that kidneys filter out
Age: Kidney function naturally declines with age
Gender: Men typically have more muscle mass than women, affecting creatinine levels
Race: The CKD-EPI formula includes an adjustment for Black individuals who tend to have higher muscle mass

Why Regular Kidney Screening Matters

Chronic Kidney Disease often has no symptoms in its early stages, making screening crucial for early detection. Early intervention can slow disease progression and prevent complications. Those with diabetes, high blood pressure, or family history of kidney disease should be especially vigilant about regular kidney function testing.

Recommended Kidney Health Products

Products to support your kidney health journey:

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Water Tracking Bottle

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Kidney Health Cookbook

$19.99

⚕️

Home Blood Pressure Monitor

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❓ Frequently Asked Questions

➕ What is GFR and why is it important?: GFR (Glomerular Filtration Rate) is the best test to measure your level of kidney function and determine your stage of kidney disease. Your doctor can calculate it from the results of your blood creatinine test, your age, body size, and gender. A normal GFR is about 90-120 mL/min/1.73m².
➕ How accurate is the GFR calculator?: This calculator uses the CKD-EPI formula, which is currently considered the most accurate method for estimating GFR. However, it provides an estimate and should not replace comprehensive medical evaluation. Actual kidney function assessment requires additional tests and clinical evaluation by a healthcare professional.
➕ What do the different GFR stages mean?: Chronic Kidney Disease is classified into 5 stages based on GFR: Stage 1 (GFR >90) - Kidney damage with normal function; Stage 2 (GFR 60-89) - Mild loss; Stage 3 (GFR 30-59) - Moderate loss; Stage 4 (GFR 15-29) - Severe loss; Stage 5 (GFR <15) - Kidney failure requiring dialysis or transplant.
➕ Why is there a race adjustment in the formula?: The race adjustment in the CKD-EPI formula accounts for observed differences in creatinine generation between Black and non-Black populations. This adjustment is based on epidemiological studies showing that Black individuals tend to have higher muscle mass and thus higher creatinine levels at the same level of kidney function. This adjustment is currently being reevaluated by medical organizations.
➕ When should I see a doctor about my kidney function?: You should consult a healthcare provider if your estimated GFR is below 60 mL/min/1.73m², if you have a rapid decline in GFR, or if you have other risk factors for kidney disease (diabetes, hypertension, family history). Always discuss your results with a medical professional for proper interpretation and guidance.

⚠️ Medical Disclaimer: This calculator provides estimates only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.