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Quickly calculate Glomerular Filtration Rate (GFR) based on the CKD-EPI formula to assess kidney health.
CKD-EPI2021/MDRD are indexed eGFR; CG is creatinine clearance in mL/min with no G-category. Numeric reference only; one value does not diagnose CKD. Reference
Enter parameters to calculate eGFR
Overview
Understand what the tool solves, how it works, and the boundaries of its data.
This adult GFR calculator lets you choose among 2021 CKD-EPI, MDRD, and Cockcroft-Gault (C-G) using age, sex, serum creatinine, and, for C-G, body weight. It calculates the selected equation at a time, so change the formula while keeping the same inputs to see how the estimates differ. It is a formula comparison aid, not a kidney-disease test.
The 2021 CKD-EPI and MDRD options estimate glomerular filtration rate and report eGFR in mL/min/1.73 m2. The C-G option estimates creatinine clearance (CrCl) in mL/min from age, serum creatinine, sex, and weight in kilograms. CrCl is not indexed to a standard body surface area, so it is a different quantity from eGFR. The C-G result does not receive a G category in this calculator.
2021 CKD-EPI creatinine: 142 x min(SCr/k, 1)a x max(SCr/k, 1)-1.2 x 0.9938age x 1.012 if female. For females, k = 0.7 and a = -0.241; for males, k = 0.9 and a = -0.302. SCr is in mg/dL.
MDRD variant: 175 x SCr-1.154 x age-0.203, multiplied by 0.742 for female. The displayed calculation does not apply a race multiplier; use it as a comparison with this stated variant, not as a substitute for a lab's reported method. NIDDK's archived MDRD form includes a race term, so this implementation is a different variant.
C-G: (140 - age) x weight in kg / (72 x SCr in mg/dL), multiplied by 0.85 for female. This returns CrCl in mL/min.
The calculator accepts serum creatinine in mg/dL or micromol/L; it converts micromol/L to mg/dL by dividing by 88.4 before calculating. Its adult age range is 18 through 120 years. NIDDK describes the CKD-EPI 2021 result as an estimate rather than a precise measurement and recommends standardized laboratory creatinine methods. NIDDK's previous-equations page documents MDRD for reference. The National Kidney Foundation describes C-G separately as creatinine clearance.
When CKD-EPI or MDRD is selected, the displayed numeric eGFR is grouped using these ranges:
| Category | eGFR (mL/min/1.73 m2) | General descriptor |
|---|---|---|
| G1 | 90 or higher | Normal or high |
| G2 | 60-89 | Mildly decreased |
| G3a | 45-59 | Mildly to moderately decreased |
| G3b | 30-44 | Moderately to severely decreased |
| G4 | 15-29 | Severely decreased |
| G5 | Below 15 | Kidney failure range |
These are GFR categories, not a complete CKD classification. The National Kidney Foundation describes CKD classification as considering cause, GFR, and albuminuria; G1 or G2 alone does not establish CKD without evidence of kidney damage.
Guide
Follow the workflow and verify inputs and outputs with practical examples.
Select CKD-EPI or MDRD for an indexed eGFR estimate. Select C-G when you specifically need to compare a creatinine-clearance estimate; this option also needs body weight in kilograms.
Use the age and sex recorded for the equation and copy serum creatinine from one lab result. Choose mg/dL or micromol/L to match the report. Changing the unit selection clears the creatinine field, so enter the number again after switching units.
The result is displayed to one decimal place. CKD-EPI and MDRD categories are assigned from the unrounded estimate before display rounding. CKD-EPI and MDRD also show a G category; C-G shows CrCl in mL/min without a G category. For a useful comparison, note equation, creatinine value and unit, age, sex, and (for C-G) weight alongside the number.
Use cases
See how the tool fits into real work and everyday tasks.
An adult reviewing a lab report can enter the reported age, sex, and creatinine, then compare the estimate with the value printed by the lab. A mismatch is a prompt to check equation and units, not proof that either result is a diagnosis.
A learner can keep one set of inputs fixed and switch among CKD-EPI, the included MDRD variant, and C-G. This shows that C-G uses weight and produces CrCl, while the other two results are indexed eGFR estimates.
Q&A
Find concise answers to common questions and confusing cases.
They use different mathematical relationships and do not all estimate the same quantity. CKD-EPI and MDRD estimate indexed eGFR; C-G estimates CrCl and includes weight. Check that age, sex, creatinine, and units match the lab record.
No. Choose one formula, read its result, then select another formula using the same inputs if you want to compare. Only C-G asks for body weight.
C-G returns creatinine clearance in mL/min, whereas G1-G5 are indexed eGFR categories in mL/min/1.73 m2. The units and estimates are not interchangeable.
No. The calculator accepts ages 18 through 120 and implements adult equations. Pediatric estimates use different methods and clinical inputs.
Notes
Review scope, result limitations, and important precautions before use.
This calculator provides arithmetic reference estimates only. It cannot diagnose CKD, confirm a clinical stage, or determine a treatment or medication dose.
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