eGFR (estimated glomerular filtration rate) is an estimate of kidney filtration based on creatinine, age, and sex. • Reported as mL/min/1.73m² (indexed to body surface area). • Used to detect, stage, and monitor chronic kidney disease (CKD). • Interpret trends over time and consider albuminuria and clinical context.

Why do I need to choose µmol/L or mg/dL?

Australia typically reports creatinine in µmol/L, while CKD-EPI equations use mg/dL internally. • This calculator converts µmol/L → mg/dL using: mg/dL = µmol/L ÷ 88.4. • Entering the wrong unit can make results look wildly incorrect.

Which equation does this calculator use?

It uses the CKD-EPI 2021 creatinine equation (race-free). • Inputs: age, sex, serum creatinine. • Output: eGFR in mL/min/1.73m². • Race coefficient is not used in this 2021 update.

Is eGFR the same as creatinine clearance (CrCl)?

No. eGFR is best for CKD staging; many drug-dosing protocols specify CrCl (Cockcroft–Gault). • Follow your hospital protocol or medicine monograph. • Use CrCl calculators when required for dosing decisions.

When can eGFR be less accurate?

Creatinine-based eGFR can be less reliable when creatinine doesn’t reflect true filtration. • Very low/high muscle mass (frailty, bodybuilding). • Rapidly changing renal function (AKI). • Pregnancy, amputations, severe liver disease.

eGFR Calculator (CKD-EPI 2021)

Estimate kidney function using the CKD-EPI 2021 race-free creatinine equation. Supports creatinine in µmol/L (AU/NZ) or mg/dL (US).

Age (years)

Sex

Serum creatinine

Tip: Most Australian pathology reports use µmol/L.

How eGFR Works

The estimated glomerular filtration rate (eGFR) is a calculated estimate of kidney filtration. It uses serum creatinine plus patient factors (age and sex) to estimate kidney function and support chronic kidney disease (CKD) staging.

In Australia, creatinine is commonly reported in µmol/L. The CKD-EPI equation uses mg/dL, so this calculator converts units automatically when you choose µmol/L.

eGFR should be interpreted with clinical context (trend over time, urine ACR/albuminuria, hydration, acute illness, muscle mass). For some medication dosing decisions, protocols may prefer creatinine clearance (CrCl) rather than eGFR.

Formula (CKD-EPI 2021)

eGFR = 142 × min(SCr/κ, 1)^α × max(SCr/κ, 1)^−1.2 × 0.9938^Age × SexFactor

κ = 0.7 (female) or 0.9 (male)

α = −0.241 (female) or −0.302 (male)

SexFactor = 1.012 (female) or 1 (male)

SCr must be mg/dL (if µmol/L: mg/dL = µmol/L ÷ 88.4)

Worked Examples

Example 1 (AU units): 60-year-old male, creatinine 90 µmol/L

Enter Age 60, Sex Male, Creatinine 90, then choose µmol/L. The calculator converts to mg/dL internally and returns eGFR and CKD stage.

Example 2 (US units): 45-year-old female, creatinine 1.0 mg/dL

Enter Age 45, Sex Female, Creatinine 1.0, and keep units as mg/dL.

Example 3: Interpreting CKD stage

If your eGFR result is 52 mL/min/1.73m², that corresponds to KDIGO category G3a.

When This Calculator Is Used

•CKD detection, staging, and monitoring over time
•Interpreting renal function in pathology results (especially µmol/L in AU/NZ)
•Pre-procedure / imaging risk discussion (contrast planning varies by protocol)
•Clinical documentation and education
•Screening and trend review in chronic disease management

Clinical safety note: eGFR is an estimate. Interpret alongside clinical context (hydration, acute illness, muscle mass, pregnancy) and urine markers (e.g., ACR). For medication dosing, follow your local guideline (some use CrCl instead of eGFR).

Related Calculators

Creatinine Clearance

Cockcroft–Gault (often for dosing)

Body Surface Area

BSA calculator

Ideal Body Weight

IBW calculator

Frequently Asked Questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

References & Sources

References focus on the CKD-EPI 2021 equation and guideline-based interpretation of eGFR/CKD staging.

CKD-EPI 2021 equation (race-free) – Inker et al. (NEJM, 2021)Journal

Primary publication describing the 2021 creatinine-based eGFR equations without race.

↗

KDIGO CKD Guidelines (staging and interpretation)Guideline

International guideline source for CKD staging and clinical interpretation frameworks.

↗

Kidney Health Australia (patient-friendly CKD/eGFR info)AU

Australian educational resources and kidney health information for patients and clinicians.

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eGFR Calculator (CKD-EPI 2021)

Estimate kidney function using the CKD-EPI 2021 race-free creatinine equation. Supports creatinine in µmol/L (AU/NZ) or mg/dL (US).

Age (years)

Sex

Serum creatinine

Tip: Most Australian pathology reports use µmol/L.

How eGFR Works

In Australia, creatinine is commonly reported in µmol/L. The CKD-EPI equation uses mg/dL, so this calculator converts units automatically when you choose µmol/L.

Formula (CKD-EPI 2021)

eGFR = 142 × min(SCr/κ, 1)^α × max(SCr/κ, 1)^−1.2 × 0.9938^Age × SexFactor

κ = 0.7 (female) or 0.9 (male)

α = −0.241 (female) or −0.302 (male)

SexFactor = 1.012 (female) or 1 (male)

SCr must be mg/dL (if µmol/L: mg/dL = µmol/L ÷ 88.4)

Worked Examples

Example 1 (AU units): 60-year-old male, creatinine 90 µmol/L

Enter Age 60, Sex Male, Creatinine 90, then choose µmol/L. The calculator converts to mg/dL internally and returns eGFR and CKD stage.

Example 2 (US units): 45-year-old female, creatinine 1.0 mg/dL

Enter Age 45, Sex Female, Creatinine 1.0, and keep units as mg/dL.

Example 3: Interpreting CKD stage

If your eGFR result is 52 mL/min/1.73m², that corresponds to KDIGO category G3a.

When This Calculator Is Used

•CKD detection, staging, and monitoring over time
•Interpreting renal function in pathology results (especially µmol/L in AU/NZ)
•Pre-procedure / imaging risk discussion (contrast planning varies by protocol)
•Clinical documentation and education
•Screening and trend review in chronic disease management

Frequently Asked Questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

eGFR Calculator (CKD-EPI 2021)

How eGFR Works

Formula (CKD-EPI 2021)

Worked Examples

When This Calculator Is Used

Related Calculators

Frequently Asked Questions

QWhat is eGFR?

QWhy do I need to choose µmol/L or mg/dL?

QWhich equation does this calculator use?

QIs eGFR the same as creatinine clearance (CrCl)?

QWhen can eGFR be less accurate?

References & Sources

eGFR Calculator (CKD-EPI 2021)

How eGFR Works

Formula (CKD-EPI 2021)

Worked Examples

When This Calculator Is Used

Related Calculators

Frequently Asked Questions

QWhat is eGFR?

QWhy do I need to choose µmol/L or mg/dL?

QWhich equation does this calculator use?

QIs eGFR the same as creatinine clearance (CrCl)?

QWhen can eGFR be less accurate?

References & Sources