# eGFR Calculator — CKD-EPI 2021 (Race-Free)
> Free eGFR calculator using the 2021 CKD-EPI race-free equation. Published in NEJM 2021. Returns eGFR in mL/min/1.73 m².

## Overview

The CKD-EPI 2021 equation estimates glomerular filtration rate from serum creatinine, age, and sex. It is the National Kidney Foundation and American Society of Nephrology recommended equation as of 2021, and replaced earlier equations that included a race coefficient. The race-free formulation is widely adopted across United States health systems and most international laboratories. eGFR is reported in mL/min/1.73 m² and is used for chronic kidney disease staging, transplant referral, and many drug-dosing decisions, although Cockcroft-Gault remains the formula many FDA labels reference for renal-dose adjustment.

## Who this is for

- Internal medicine and nephrology trainees
- Hospitalists evaluating renal function trends
- APPs managing chronic kidney disease

## How to interpret the result

| Score / band | Meaning |
|---|---|
| ≥ 90 | G1 — normal or high (interpret with albuminuria). |
| 60–89 | G2 — mildly decreased. |
| 45–59 | G3a — mild-to-moderate decrease. |
| 30–44 | G3b — moderate-to-severe decrease. |
| 15–29 | G4 — severely decreased. |
| < 15 | G5 — kidney failure. |

## Cited source

**KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD** (2024) — KDIGO

_Primary publication:_ Inker LA et al., NEJM 2021 (CKD-EPI 2021)

## FAQs

### Is the CKD-EPI 2021 equation race-free?

Yes. CKD-EPI 2021 (Inker, NEJM 2021) does not use race. The NKF-ASN Task Force endorsed race-free reporting in September 2021.

### Should I use eGFR or creatinine clearance for drug dosing?

Many FDA labels reference Cockcroft-Gault creatinine clearance (mL/min). For most clinical staging purposes, eGFR (mL/min/1.73 m²) is used. When in doubt for drug dosing, default to the formula referenced in the FDA label or your institutional pharmacy.

### When does eGFR mislead?

Acute kidney injury (non-steady-state creatinine), extreme body habitus, amputees, severe liver disease, and certain ethnic groups can all distort eGFR. Cystatin C-based equations are alternatives in those settings.

### What is the cystatin-C alternative?

CKD-EPI 2021 cystatin-C and CKD-EPI 2021 creatinine + cystatin-C improve accuracy in some populations (e.g. amputees, sarcopenic patients). Order if available and indicated.

### Does eGFR ≥ 90 mean kidneys are normal?

No. Normal eGFR with significant albuminuria (≥ 30 mg/g) still meets CKD criteria (G1A2 or G1A3). Always pair eGFR with urine albumin-creatinine ratio.

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_Rounds AI is a citation-first clinical AI assistant. It supports clinical reasoning by surfacing cited information and is not a substitute for independent clinical judgement._