# GFR Calculator

> Estimate race-free kidney filtration with the 2021 CKD-EPI creatinine equation for adults or the CKiD U25 creatinine equation for ages 1–25.

Page: https://askcalculators.com/calculator/gfr-calculator/
Definition: https://askcalculators.com/calculator/gfr-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/gfr-calculator/schema.json
Version: 2.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/gfr-calculator/?ageGroup=adult&age=50&sex=male&creatinineUnit=mgdl&creatinine=1

## Inputs
- ageGroup: Equation population; type=select; required; default=adult; values=adult|pediatric
- age: Age; type=number; required; default=50; min=1; max=120
- sex: Sex used by equation; type=select; required; default=male; values=male|female
- creatinineUnit: Serum creatinine unit; type=select; required; default=mgdl; values=mgdl|umol
- creatinine: Serum creatinine; type=number; required; default=1; min=0.05; max=3000
- heightCm: Height for CKiD U25; type=number; required; default=140; min=40; max=250; showWhen=ageGroup:pediatric

## Outputs
- egfr: Estimated GFR; format=number; primary
- category: GFR category; format=text
- equation: Equation used; format=text
- creatinineMgDl: Creatinine used; format=number
- interpretation: Interpretation note; format=text

## Formula
Adult 2021 CKD-EPI: 142×min(SCr/κ,1)^α×max(SCr/κ,1)^−1.200×0.9938^age×1.012 if female; CKiD U25: κ(age,sex)×height(m)/SCr.

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.

Notice: eGFR is an estimate, not a diagnosis. Kidney assessment depends on trends, albuminuria, clinical context, and appropriately standardized laboratory measurements.