GFR Calculator

Estimate kidney function with the race-free CKD-EPI 2021 equation. A physician must interpret any result.

MedicalScience-backed formula

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Fill in the fields, then calculate

Important: This estimate does not diagnose kidney disease. Only a qualified physician can interpret eGFR alongside your full medical picture. Do not change any treatment based on this number.

Sex

Age (years)Enter your age.

Serum creatinine (mg/dL)Enter serum creatinine.

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Enter your details and tap Calculate to see your results appear here.

Result

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What eGFR Estimates

The glomerular filtration rate shows how well your kidneys filter waste from your blood. The CKD-EPI 2021 equation estimates it from a blood creatinine test, your age, and your sex.

Your inputs translate into a careful, conservative estimate.

The 2021 version removed race from the formula, making it fairer and more consistent.

This is an estimate. Doctors confirm kidney health with repeat tests and your wider history.

How to Use This Calculator

Select your sex and enter your age.
Enter your serum creatinine from a blood test.
Tap Calculate for your estimated GFR.

The Formula Used

eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × (1.012 if female)

Scr: Serum creatinine in mg/dL.
κ: 0.7 for women, 0.9 for men.
α: −0.241 for women, −0.302 for men.

Understanding Your Results

G1 Normal

90+ mL/min

Normal kidney function.

G2 Mild

60 to 89 mL/min

Mildly reduced, often normal with age.

G3 Moderate

30 to 59 mL/min

Moderately reduced. See a doctor.

G4-G5 Severe

Under 30 mL/min

Severely reduced. Needs medical care.

Tips to Improve

Discuss any result with your doctor.
Stay hydrated unless advised otherwise.
Manage blood pressure and blood sugar.
Use medications only as prescribed.

Frequently Asked Questions

Can this diagnose kidney disease?

No. It is an estimate. A physician confirms kidney health with repeat tests and your history.

What is a normal eGFR?

Above 90 is normal, though it naturally declines a little with age.

Where do I get my creatinine value?

A standard blood test reports it. Use the most recent result.

Scientific References

Inker, L. A., et al. (2021). New creatinine- and cystatin C-based equations without race. New England Journal of Medicine, 385(19), 1737–1749.
Levey, A. S., et al. (2009). A new equation to estimate glomerular filtration rate. Annals of Internal Medicine, 150(9), 604–612.
Kidney Disease: Improving Global Outcomes. (2024). KDIGO clinical practice guideline for CKD.

Disclaimer: The calculators and information on this site are provided for general informational use only and do not replace professional medical advice, diagnosis, or treatment. Always speak with a qualified healthcare professional about any questions regarding your health.