GFR Calculator
Calculate your estimated Glomerular Filtration Rate (eGFR) to assess kidney function for adults and children using clinically validated formulas.
Kidney Function Assessment
Enter patient information to calculate estimated GFR and CKD stage
Normal range: 0.6-1.2 mg/dL (varies by lab)
eGFR Result
Enter patient information to calculate eGFR.
Understanding GFR & CKD Stages
CKD Stages
G1: ≥90Normal
G2: 60-89Mildly decreased
G3a: 45-59Mild-moderate
G3b: 30-44Moderate-severe
G4: 15-29Severe
G5: <15Kidney failure
Formula Comparison
CKD-EPI 2021:
Most current, race-free formula recommended by guidelines
MDRD:
Traditional formula, may underestimate at higher GFR levels
Schwartz Formula:
Pediatric formula for children aged 0-17 years
Clinical Significance
- Normal GFR: 90-120 mL/min/1.73 m² in healthy adults
- CKD diagnosis: GFR <60 for ≥3 months
- Referral to nephrology: Usually at GFR <30
- Dialysis consideration: GFR <15 or symptomatic
Limitations
- Less accurate in extremes of age, body size, or muscle mass
- May be inaccurate in acute kidney injury
- Requires stable creatinine levels
- Consider cystatin C-based equations for better accuracy
How to Use This Calculator
Step-by-step guide to get accurate results
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What is a GFR Calculator?
A GFR (Glomerular Filtration Rate) Calculator estimates how well your kidneys are filtering blood. It uses your age, sex, and serum creatinine levels to provide an estimated GFR (eGFR) and identify your CKD (Chronic Kidney Disease) stage. This tool is essential for monitoring kidney health in both adults and children.
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How the GFR Calculator Works
Inputs Required
Age, Sex, Serum Creatinine (mg/dL or μmol/L), Pediatric or Adult selection.
Formulas Used
CKD-EPI (most accurate for adults), MDRD (commonly used in CKD monitoring), and Schwartz Formula (for pediatric GFR calculation).
What Happens Next
After entering details, the calculator estimates your eGFR and identifies CKD stage if applicable.
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Why Use a GFR Calculator?
Clear Kidney Health Insights
Quickly understand how efficiently your kidneys filter blood.
CKD Monitoring
Track progression or detect early-stage kidney disease.
Personalized Tracking
Separate calculators for adults and children ensure accuracy.
Formula Comparison
Check results with CKD-EPI vs MDRD for optimal accuracy.
Convenience
Fast, free, and online without manual calculations.
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Tips to Improve Kidney Function Naturally
Stay Hydrated
Drink enough water daily to support kidney filtration.
Control Blood Pressure & Blood Sugar
Helps prevent CKD progression.
Eat a Kidney-Friendly Diet
Limit salt, processed foods, and excess protein intake.
Avoid Nephrotoxic Medications
Only take medications that affect kidneys if prescribed.
Exercise Regularly
Supports cardiovascular health, indirectly improving kidneys.
Regular Monitoring
Use a GFR calculator online to track trends over time.
Frequently Asked Questions
What is GFR and why is it important?
GFR measures how efficiently your kidneys filter blood, indicating overall kidney health.
How do I calculate GFR online?
Enter your age, sex, and serum creatinine into the calculator to get an eGFR value.
What is the normal GFR range for adults?
Typically 90–120 mL/min/1.73 m², though it varies with age and sex.
How does GFR compare to creatinine levels?
GFR adjusts for age, sex, and body size, giving a more complete picture than creatinine alone.
Can a pediatric GFR calculator help children?
Yes, the Schwartz formula is used to estimate kidney function in children.
Which is better: CKD-EPI or MDRD formula?
CKD-EPI is more accurate for adults with normal or mildly reduced kidney function, while MDRD is widely used in CKD monitoring.
Can I track my kidney function over time?
Yes, regular tracking with the GFR Calculator helps monitor changes and detect early issues.
Is this GFR calculator suitable for irregular kidney function?
Yes, it adjusts for age, sex, and adult/pediatric status to remain reliable.
Are free GFR calculators as accurate as paid ones?
Yes, our free calculator uses the same validated formulas as professional tools.
How can I improve GFR naturally?
Hydration, healthy diet, blood pressure control, exercise, and regular monitoring can help maintain or improve kidney function.