GFR Calculator
Estimate your kidney function with precision
GFR Calculator for Adults
Advanced kidney function assessment for patients 18+ years
GFR Calculator for Children
Pediatric kidney function assessment for patients ≤18 years
Calculation Results
MDRD Equation
-
mL/min/1.73 m²
CKD-EPI Formula
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mL/min/1.73 m²
Mayo Formula
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mL/min/1.73 m²
Chronic Kidney Disease Stages
| Stage | Description | GFR Range |
|---|---|---|
| Normal | Normal kidney function | 90+ mL/min/1.73 m² |
| Stage 1 | Kidney damage with normal function | 90+ with proteinuria |
| Stage 2 (Mild) | Mild loss of kidney function | 60-89 |
| Stage 3 (Moderate) | Moderate loss of kidney function | 30-59 |
| Stage 4 (Severe) | Severe loss of kidney function | 15-29 |
| Stage 5 (Kidney Failure) | Kidney failure | < 15 |
Our free GFR Calculator estimates your kidney function using four clinically validated formulas — CKD-EPI, MDRD, and Mayo for adults, and Schwartz for children. Enter your serum creatinine, age, and sex (or height for children) to get an instant eGFR result in mL/min/1.73 m², along with your corresponding chronic kidney disease stage.
How to Use This Calculator
1
Choose your group — Adults (18+) or Children (≤18) — using the tabs at the top.
2
Enter your serum creatinine value from a recent blood test, in mg/dL or μmol/L.
3
For adults, add age, sex, and race. For children, add height instead.
4
Click Calculate GFR to instantly see results from multiple validated formulas.
5
Compare your result against the CKD stage table to understand what it means.
GFR Result Reference Guide
| GFR Range | Status | What To Do |
|---|---|---|
| 90+ | Normal | Maintain healthy habits, routine checkups |
| 60–89 | Mild Decrease | Monitor trends, discuss with your doctor |
| 30–59 | Moderate CKD | Medical evaluation recommended |
| 15–29 | Severe CKD | Active specialist management needed |
| Below 15 | Kidney Failure | Immediate medical attention required |
Frequently Asked Questions
A GFR of 90 mL/min/1.73 m² or higher is generally considered normal kidney function in healthy adults. GFR naturally declines somewhat with age, so slightly lower values can still be unremarkable in older adults.
MDRD, CKD-EPI, and Mayo are different validated formulas for estimating GFR, each developed using different study populations and methods. They can produce slightly different results, which is why doctors often consider more than one before drawing conclusions.
No. This tool provides an estimate for informational purposes only. A proper kidney disease diagnosis requires lab testing, medical history, and evaluation by a qualified healthcare provider.
The Schwartz formula is specifically designed for pediatric patients and uses height and creatinine rather than age, sex, and race, which makes it more reliable for children's growing bodies.
Want to Understand GFR in Depth?
Read our complete guide — what affects your GFR, how to improve kidney function, CKD stages explained, and when to see a doctor.