GFR Calculator

Q: What is eGFR?

Estimated Glomerular Filtration Rate — a measure of how well your kidneys filter waste from the blood, calculated from a blood creatinine level, age, and sex.

Q: What changed in the 2021 CKD-EPI equation?

The 2021 update removed the race coefficient used in earlier versions (2009 CKD-EPI and MDRD), following evidence that race is not a reliable biological proxy for kidney function and its use could delay care for Black patients.

Q: Does a low eGFR always mean kidney disease?

Not necessarily — a single low reading can result from dehydration, certain medications, or lab variation. A formal CKD diagnosis requires either a persistently low eGFR (3+ months) or other evidence of kidney damage, assessed by a doctor.

Estimate your glomerular filtration rate (eGFR) — a measure of kidney function — using the 2021 CKD-EPI creatinine equation, from a serum creatinine lab result.

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Enter your serum creatinine, age, and sex to estimate your glomerular filtration rate (eGFR) using the 2021 CKD-EPI equation.

Serum creatinine *

mg/dL

Age *

years

Sex

Male

Female

Your result

94.6 mL/min/1.73m²

Estimated GFR

CKD stageG1

AI explanation

Formula

2021 CKD-EPI creatinine equation (race-free): eGFR = 142 × min(Scr/κ,1)^α × max(Scr/κ,1)^-1.2 × 0.9938^age × (1.012 if female)

Worked example

Male, age 50, creatinine 1.0 mg/dL

Worked example: Male, age 50, creatinine 1.0 mg/dL
Field	Value
Serum creatinine	1
Age	50
Sex	male
CKD stage	G1

Assumptions

Uses the 2021 CKD-EPI creatinine equation, the current NKF/ASN task force-recommended formula (replacing earlier race-based versions).
Serum creatinine must come from a recent lab test — this calculator does not measure creatinine itself.
CKD stages: G1 (>=90, normal), G2 (60-89, mildly decreased), G3a (45-59), G3b (30-44), G4 (15-29), G5 (<15, kidney failure) — staging also requires evidence of kidney damage for a formal CKD diagnosis, which this calculator does not assess.
This is a medically sensitive estimate — always interpreted alongside clinical context by a qualified healthcare professional, never as a standalone diagnosis.

Frequently asked questions

What is eGFR?

Estimated Glomerular Filtration Rate — a measure of how well your kidneys filter waste from the blood, calculated from a blood creatinine level, age, and sex.

What changed in the 2021 CKD-EPI equation?

The 2021 update removed the race coefficient used in earlier versions (2009 CKD-EPI and MDRD), following evidence that race is not a reliable biological proxy for kidney function and its use could delay care for Black patients.

Does a low eGFR always mean kidney disease?

Not necessarily — a single low reading can result from dehydration, certain medications, or lab variation. A formal CKD diagnosis requires either a persistently low eGFR (3+ months) or other evidence of kidney damage, assessed by a doctor.

Related calculators

Sources

New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race — New England Journal of Medicine. Effective 23-09-2021, reviewed 13-09-2026.
KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease — Kidney Disease: Improving Global Outcomes (KDIGO). Effective 01-01-2013, reviewed 13-09-2026.

This calculator provides a general estimate only and does not constitute a medical diagnosis. Kidney function must be assessed and interpreted by a qualified healthcare professional using your full clinical history.

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