Estimated eGFR Calculator
Assess your kidney function instantly. Calculate your Estimated Glomerular Filtration Rate (eGFR) using your Serum Creatinine level to understand your renal health stage.
CKD Stage
Identify Stage 1-5
Creatinine
Input lab value
CKD-EPI 2021
Latest standard
Filtration Rate
mL/min/1.73m²
What is eGFR?
Estimated Glomerular Filtration Rate (eGFR) is the best test to measure your level of kidney function and determine your stage of kidney disease.
The Body's Filter
Your kidneys contain millions of tiny filters called glomeruli. They remove waste from your blood. The rate at which they filter this blood is your GFR. Since we cannot measure GFR directly without complex procedures, we "estimate" it (eGFR) using the level of Creatinine in your blood, along with your age and gender.
The "Percentage" Analogy
Think of eGFR roughly as a percentage. A score of 100 means your kidneys are working at 100%. A score of 50 means they are filtering at 50% capacity.
Creatinine Levels
Creatinine is a waste product from muscle wear and tear. If kidneys are damaged, creatinine builds up in the blood.
CKD Staging
eGFR is the primary number used by doctors to stage Chronic Kidney Disease (CKD) from 1 to 5.
2021 Standard
We use the CKD-EPI 2021 formula, which is recommended by the National Kidney Foundation because it is more accurate and unbiased.
Unit Converter
Input your creatinine in mg/dL (US) or µmol/L (International). The calculator handles the math automatically.
Stage Identifier
Instantly see if you are in Stage 1 (Normal), Stage 3 (Moderate), or Stage 5 (Failure) based on your result.
Why Use Our Tool?
Clarifies Lab Results
Lab reports often just list "eGFR" with a number. We tell you what that number *means* for your life.
Updated Protocol
Many older calculators use the MDRD formula or the 2009 CKD-EPI which included a race multiplier. Ours uses the 2021 protocol for equity and accuracy.
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How to Use the eGFR Calculator
Get accurate results from your blood work.
Find Creatinine
Look at your blood test results for "Serum Creatinine" or "Creatinine, Serum." It will be a number like 0.9, 1.2, or 85.
Select Units
Check the unit next to your creatinine number. Is it mg/dL (US standard) or µmol/L (International)? Select the matching tab in the calculator.
Calculate
Enter your age and gender (creatinine reference ranges differ by gender). Click calculate to see your eGFR and CKD Stage.
Understanding the Inputs
What exactly is "Serum Creatinine" and where do you find it?
Serum Creatinine
Creatinine is a chemical waste product produced by your muscle metabolism. Healthy kidneys filter it out of the blood and into urine.
How to Measure
This requires a simple blood test (Basic Metabolic Panel). You cannot measure it at home. Look for "Creatinine" on your lab report.
Units of Measurement
Different countries use different scales. It is crucial to select the right one, or your result will be wrong by a factor of 88.
- mg/dL USA Standard. Typical range: 0.6 to 1.2.
- µmol/L International Standard. Typical range: 53 to 106.
Calculate Your eGFR
Based on CKD-EPI (2021) formula.
CKD Stages Guide
Classification according to National Kidney Foundation.
Understanding the Results
What affects your numbers?
Muscle Mass
Creatinine comes from muscle. Bodybuilders may have high creatinine (low eGFR) but healthy kidneys. The elderly may have low creatinine but poor kidney function.
Hydration
Dehydration concentrates creatinine in the blood, temporarily lowering your eGFR. Always drink water before a blood test.
Diet
Eating a large amount of cooked meat right before a test can temporarily raise creatinine levels. Fasting is often recommended.
Applications of eGFR
Why doctors track this number.
Early Detection
Kidney disease is silent. You can lose 90% of function before feeling symptoms. eGFR trends over time allow doctors to spot decline years before failure occurs.
Medication Safety
Many drugs (like antibiotics and NSAIDs) are cleared by the kidneys. If eGFR is low, doctors must reduce the dosage to prevent toxic buildup in the body.
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Frequently Asked Questions
Why does age lower eGFR?
Kidney function naturally declines with age, about 1% per year after age 40. An eGFR of 60 might be normal for an 80-year-old but concerning for a 20-year-old.
Why was the race factor removed?
Older formulas included a multiplier for African Americans based on flawed assumptions about muscle mass. In 2021, the NKF removed this to ensure equitable healthcare and earlier diagnosis for all patients.
Can eGFR improve?
Yes. If the cause is acute (dehydration, infection, medication), eGFR can bounce back. Chronic damage is usually permanent but can be slowed down with diet and blood pressure control.
Is this accurate for children?
No. This calculator uses the CKD-EPI 2021 formula, which is validated for adults (18+). For children, the "Bedside Schwartz" formula is typically used.