GFR Calculator: Estimate Your Kidney Function
Free estimated GFR from serum creatinine — MDRD, CKD-EPI 2009, Mayo Quadratic for adults, and Schwartz for children. Supports mg/dL and µmol/L.
Inputs
GFR Calculator: Estimate Your Kidney Function (Glomerular Filtration Rate)
The Glomerular Filtration Rate (GFR) is widely considered the best indicator of overall kidney function. It tells you how well your kidneys are filtering waste from your blood.
Our free GFR Calculator provides accurate estimates using the most commonly used medical formulas, matching the standards found on leading health calculators.
Important: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice or laboratory testing. Always consult a doctor for interpretation of results.
How Our GFR Calculator Works
The calculator automatically switches between Adult and Child modes based on age and applies the appropriate formulas.
Inputs
- Age
- Gender
- Serum Creatinine (supports both mg/dL and µmol/L)
- Race (for MDRD and CKD-EPI)
- Height (required for children)
Formulas Used for Adults (18+)
- MDRD (Modification of Diet in Renal Disease)
- CKD-EPI 2009 (most commonly referenced)
- Mayo Quadratic
For Children (≤18 years)
- Schwartz Formula
All results are expressed in mL/min/1.73 m² (standardized to average body surface area).
Understanding Your GFR Results
| GFR Level (mL/min/1.73 m²) | Kidney Function Stage | Description |
|---|---|---|
| 90 or higher | Stage 1 | Normal or high |
| 60 – 89 | Stage 2 | Mildly decreased |
| 45 – 59 | Stage 3a | Mild to moderate decrease |
| 30 – 44 | Stage 3b | Moderate to severe decrease |
| 15 – 29 | Stage 4 | Severely decreased |
| Below 15 | Stage 5 | Kidney failure |
Why Use This GFR Calculator?
- Get three different adult estimates for better comparison
- Supports both creatinine units (mg/dL and µmol/L)
- Includes pediatric calculation
- Fast and easy to use
- Helpful for people with diabetes, hypertension, or family history of kidney disease
Example Calculation
Male, 50 years old, Serum Creatinine = 1.0 mg/dL, Not Black
- MDRD ≈ 75.5 mL/min/1.73 m²
- CKD-EPI ≈ 84.2 mL/min/1.73 m²
- Mayo Quadratic ≈ 88.1 mL/min/1.73 m²
Tips for Kidney Health
- Stay well hydrated
- Control blood pressure and blood sugar levels
- Maintain a healthy weight
- Avoid long-term overuse of NSAIDs (ibuprofen, etc.)
- Get regular check-ups if you have risk factors
Disclaimer: The GFR values provided are mathematical estimates only. They should not be used for self-diagnosis or medical decisions. Actual kidney function assessment requires professional lab tests and clinical evaluation by a healthcare provider.
Ready to check your estimated GFR? Enter your details above to calculate your kidney function using multiple trusted formulas.