GFR Calculator
Estimate your glomerular filtration rate (eGFR) using the CKD‑EPI 2021 formula — no race coefficient needed.
⚠ This tool provides an estimate and is not a substitute for professional medical advice, diagnosis, or treatment.
Understanding Your GFR and Kidney Health
Glomerular filtration rate (GFR) is the best overall indicator of kidney function. It measures how much blood your kidneys filter each minute. Because directly measuring GFR is complex, doctors use estimated GFR (eGFR), which is calculated from your blood creatinine level, age, and gender.
Why Use the CKD‑EPI 2021 Equation?
Our calculator uses the latest CKD‑EPI 2021 formula, recommended by the National Kidney Foundation. Unlike older equations, it does not incorporate race, making it more equitable and accurate for all populations. The result is expressed in milliliters per minute per 1.73 m² of body surface area.
eGFR Stages and What They Mean
Your eGFR result falls into one of the following chronic kidney disease (CKD) stages. Note that staging is only applicable if kidney damage has been confirmed (e.g., through urine tests or imaging).
| Stage | eGFR (mL/min/1.73 m²) | Interpretation |
|---|---|---|
| 1 | ≥ 90 | Normal kidney function, but possible kidney damage* |
| 2 | 60 – 89 | Mildly reduced kidney function* |
| 3a | 45 – 59 | Mild to moderate reduction |
| 3b | 30 – 44 | Moderate to severe reduction |
| 4 | 15 – 29 | Severely reduced kidney function |
| 5 | < 15 | Kidney failure (end‑stage renal disease) |
*Stage 1 and 2 require other evidence of kidney damage (protein in urine, abnormal imaging) to be considered CKD.
Tips for Keeping Your Kidneys Healthy
Whether your eGFR is normal or reduced, healthy habits can protect your kidneys:
- Stay hydrated and follow a balanced, low‑sodium diet.
- Keep blood pressure and blood sugar under control.
- Avoid prolonged use of over‑the‑counter painkillers like NSAIDs.
- Maintain a healthy weight and stay physically active.
- Don’t smoke, and limit alcohol intake.
- Get regular kidney function check‑ups if you have diabetes, hypertension, or a family history of kidney disease.
When to See a Doctor
An eGFR below 60 mL/min/1.73 m² that persists for three months or more indicates chronic kidney disease. If your result is unusually low (or high) and you are concerned, please consult your healthcare provider. Early detection can slow progression and prevent complications.
Disclaimer: This calculator is for educational purposes only and does not constitute medical advice. Always seek the guidance of a qualified health professional with any questions regarding your health.
