GFR Calculator

Glomerular filtration rate (GFR) is the best overall index of kidney function. Normal GFR varies according to age, sex, and body size, and declines with age. The National Kidney Foundation recommends using the CKD-EPI Creatinine Equation (2009) to estimate GFR.


NKF and the American Society of Nephrology have convened a Task Force to focus on the use of race to estimate GFR. Read more about the task force here.

Serum Creatinine:
Serum Cystatin C: mg/L
Age: Years
Standardized Assays:
These equations are valid only with standardized creatinine and cystatin methods. To learn more, click here.
Remove body surface adjustment:
  • The GFR estimating equations on this page will automatically adjust for body surface area unless “yes” is selected for “remove body surface adjustment.”
  • Drug dosing should be based on GFR which is not adjusted for body surface area.


CKD-EPI creatinine equation (2009) mL/min
CKD-EPI creatinine-cystatin equation (2012) mL/min
CKD-EPI cystatin C equation (2012) mL/min
MDRD study equation mL/min

For persons under 18 years of age, use the pediatric GFR calculator.

Is it CKD?

Either of the following must be present for ≥3 months to be CKD:

  • GFR less than 60 ≥3 months
  • ACR ≥30 mg/g or other markers of kidney damage

Click to learn more.

Equation used to estimate GFR?

What is the patient’s ACR?†

Based on the information supplied:

GFR category is:‡    see note below
ACR category is:**
CKD classification is:
Risk of progression is:
Frequency of monitoring should be:
Referral to a nephrologist is:

In the absence of evidence of kidney damage, neither GFR category G1 nor G2 fulfill the criteria for CKD.

† Neither the category of GFR nor the category of albuminuria alone can fully capture prognosis of CKD. Persistent and increased albuminuria has been shown to be an independent risk factor for CKD progression.

‡In the absence of evidence of kidney damage, neither GFR category G1 nor G2 fulfill the criteria for CKD.

**ACR 30-300 mg/g for > 3 months indicates CKD.


Formulas About CKD

CKD Risk Map

Clinician Tools

Kidney Failure Risk Equation