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GFR Calculator (CKD-EPI 2021)

Estimate eGFR in mL/min/1.73m2 using the 2021 CKD-EPI creatinine equation (race-free) from serum creatinine, age, and sex.

Details

Uses the 2021 CKD-EPI creatinine equation. Does not use a race variable. Result is normalized to 1.73 m2 body surface area.

Result

eGFR--
CKD stage (KDIGO)--
Stage description--

A single eGFR value does not diagnose CKD. Stage requires confirmation over at least three months. This result is for educational reference only.

2021 CKD-EPI creatinine equationNEJM / National Kidney FoundationCalculates client side
Naomi Foster
By Naomi Foster, health writer. Last updated .

How Is eGFR Calculated

The GFR calculator above uses the 2021 CKD-EPI creatinine equation, the current standard for estimating glomerular filtration rate in adults. It takes serum creatinine, age, and sex as inputs and returns eGFR in mL/min/1.73 m2.

Formula (2021 CKD-EPI, female). eGFR = 142 x (Scr / 0.7)exponent x (0.9938)age. Exponent is -0.241 if Scr is 0.7 or below; -1.200 if Scr is above 0.7.
Formula (2021 CKD-EPI, male). eGFR = 142 x (Scr / 0.9)exponent x (0.9938)age. Exponent is -0.302 if Scr is 0.9 or below; -1.200 if Scr is above 0.9.

The 2021 revision removed the race coefficient that appeared in the 2009 version. The National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) recommended this change in 2021 following a joint task force review.

What eGFR means by CKD stage

The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines classify chronic kidney disease by eGFR as follows:

Source

The equation is described in: Inker LA, Eneanya ND, Coresh J, et al. "New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race." New England Journal of Medicine, 2021. See also the National Kidney Foundation eGFR calculator and NIDDK eGFR resources for clinicians.

Things to Know Before Using This eGFR

An eGFR result needs to persist for three months or longer before it confirms a CKD stage. One measurement, on its own, is not a diagnosis. Kidney function estimates also shift with hydration, recent illness, and certain medications, so a low reading on a bad day is not automatically a red flag.

Two related pages worth a look if kidney function is on your mind: drug dosing usually leans on a Cockcroft-Gault based clearance figure rather than eGFR, and patients with low albumin alongside reduced kidney function may want to check how albumin skews a calcium reading.

Before you read too much into this. The number above comes from one published equation and nothing else. Bring it to a clinician who has your labs and history, not the other way around.
What people ask about GFR

GFR FAQs

What should my estimated GFR be for my age?

A healthy eGFR is generally 90 mL/min/1.73m2 or above. eGFR does tend to decline with age: many adults over 70 have an eGFR in the 60 to 89 range without kidney disease. What matters most is the trend over time and whether there is also evidence of kidney damage such as protein in the urine. Only a healthcare provider can interpret your result in context.

How do I calculate my GFR?

The 2021 CKD-EPI equation calculates eGFR from serum creatinine, age, and sex. The formula uses different exponents depending on whether creatinine is above or below a sex-specific threshold (0.7 mg/dL for females, 0.9 mg/dL for males). This calculator applies those exponents automatically.

What is an alarming GFR?

An eGFR below 60 mL/min/1.73m2 that persists for three months or longer is considered CKD stage G3a or lower. An eGFR below 15 indicates kidney failure (stage G5). A sudden drop in eGFR can also be significant regardless of the absolute number. Speak with a healthcare provider if your eGFR is low or falling.

What is the new eGFR formula?

The 2021 CKD-EPI creatinine equation is the current standard recommended by the National Kidney Foundation and the American Society of Nephrology. It removed the race variable that was present in the 2009 version. It uses only serum creatinine, age, and sex.