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GFR Calculator

Estimated GFR by CKD-EPI 2021, MDRD and Cockcroft-Gault.

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Every equation

EquationResultUnitsNotes

CKD stages

StageeGFRDescription

Stages G1 and G2 are only classified as chronic kidney disease when there is other evidence of kidney damage, such as albuminuria or an abnormal scan. A reduced eGFR on a single reading is not a diagnosis.

eGFR (CKD-EPI 2021)

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Summary

CKD stage—
MDRD—
Cockcroft-Gault—
Creatinine used—

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Against a normal eGFR of 90 and above

An educational calculator. CKD-EPI 2021 is the current recommended equation and removed the race coefficient earlier versions carried, because it had no biological basis and systematically delayed care for Black patients. Results must be interpreted by a clinician alongside the rest of the picture.

Quick Tool Overview

The GFR Calculator estimates glomerular filtration rate from serum creatinine using CKD-EPI 2021, MDRD and Cockcroft-Gault together, and reports the chronic kidney disease stage the result falls into. It is an educational tool, not a substitute for clinical interpretation.

What it does
Estimates eGFR and creatinine clearance from a lab value
You give it
Serum creatinine, age, sex and weight
You get back
Three equation results and the matching CKD stage
Best for
Understanding a lab report and clinical education
Calculators Free, unlimited use No sign-up Runs in your browser

About the GFR Calculator

Estimate glomerular filtration rate from serum creatinine, age and sex, and see which chronic kidney disease stage the result falls into. Three equations are calculated together: CKD-EPI 2021, MDRD, and Cockcroft-Gault for creatinine clearance.

CKD-EPI 2021 is the current recommended equation and is the one to use by default. It is notable for having removed the race coefficient that earlier versions carried, a change made because that coefficient had no biological basis and systematically delayed care for Black patients. Cockcroft-Gault is retained here because a good deal of drug dosing guidance is still written against creatinine clearance rather than eGFR. This is an educational tool and not a substitute for interpretation by a clinician.

Key features of the GFR Calculator

CKD-EPI 2021 as the default

The current recommended equation, which removed the race coefficient earlier versions carried.

Three equations compared

MDRD still appears on many lab reports and Cockcroft-Gault still underpins drug dosing, so both are shown.

Both creatinine units

mg/dL and µmol/L are accepted and converted, which is where most manual errors happen.

CKD stage with meaning

G1 through G5 with the note that G1 and G2 need other evidence of damage to count as disease.

Explains the 2021 change

Why the race coefficient was removed, rather than presenting the equation without context.

How to use the GFR Calculator

  1. 1

    Enter serum creatinine

    In mg/dL or µmol/L — the unit is converted for you.

  2. 2

    Add age and sex

    Both are coefficients in every equation. Weight is also needed for Cockcroft-Gault.

  3. 3

    Compare the equations

    CKD-EPI 2021, MDRD and Cockcroft-Gault are shown together, since they can differ meaningfully.

  4. 4

    Read the stage

    The CKD stage from G1 to G5 that your eGFR falls into, with what each stage means.

Frequently asked questions

Above 90 mL/min/1.73m² is normal kidney function. Values decline naturally with age, so a figure in the 60s can be unremarkable in an older adult.

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