GFR Calculator

Understand eGFR, creatinine, and kidney function

What eGFR means

Estimated glomerular filtration rate (eGFR) is a widely used indicator of kidney function. It reflects how well your kidneys filter blood relative to a standardized body surface area of 1.73 m². eGFR trends over time help students, clinicians, and patients understand renal health.

CKD‑EPI 2021 equation

This calculator uses the CKD‑EPI 2021 race‑free creatinine equation for adults, incorporating serum creatinine, age, and sex. Removing the race multiplier improves equity while maintaining practical accuracy. Results are estimates and should be interpreted in clinical context.

CKD staging

Chronic kidney disease (CKD) staging groups eGFR into G1–G5 levels. Staging informs monitoring frequency, medication choices, and referrals. Albuminuria categories (A1–A3) and additional tests often refine risk beyond eGFR alone.

Practical guidance

• Check units: Creatinine may be reported in mg/dL or µmol/L; choose the correct unit to avoid errors.
• Follow trends: Serial eGFR values, not a single reading, guide decisions.
• Context matters: Hydration, medications, muscle mass, and acute illness can influence creatinine and eGFR.

Global and responsive design

The tool supports global units, displays well on mobiles, iPads, tablets, laptops, and desktops, and avoids sliders for accessibility. It’s designed for students and professionals seeking clarity and consistency.

Safety and limitations

This educational tool does not replace professional judgment. For concerning symptoms, rapid changes, pregnancy, pediatric cases, or specialized scenarios, consult local clinical guidance.

Frequently asked questions

• HOW TO calculate eGFR with this tool? Enter age, sex, serum creatinine, and the correct unit (mg/dL or µmol/L). The calculator applies the CKD‑EPI 2021 race‑free formula and shows your eGFR and CKD stage.
• HOW TO convert creatinine units? Select µmol/L or mg/dL in the unit field. The calculator converts internally (1 mg/dL ≈ 88.4 µmol/L).
• HOW TO interpret CKD stages? G1 ≥ 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 < 15 mL/min/1.73 m². Trends and albuminuria inform risk beyond eGFR alone.
• HOW TO improve result accuracy? Use recent lab values, correct units, and stable clinical conditions. Compare multiple measurements over time.
• HOW TO use eGFR in clinical planning? Use staging to guide monitoring, medication dosing, and referrals. Always apply local protocols and clinician judgment.