eGFR Calculator (CKD-EPI 2021)

Estimate your kidney function using the 2021 CKD-EPI equation, the current clinical standard. This race-free equation provides accurate eGFR for adults and determines CKD staging.

Serum Creatinine *

Age (years) *

For adults 18 years and older

Sex *

What is eGFR?

Estimated Glomerular Filtration Rate (eGFR) measures how well your kidneys filter waste from your blood. It's expressed in mL/min/1.73m² and is the best overall indicator of kidney function. This calculator uses the 2021 CKD-EPI equation, which removed race as a variable for more equitable assessment.

How to Use This Calculator

Enter your serum creatinine from a recent blood test
Select the unit (mg/dL or µmol/L)
Enter your age (must be 18 or older)
Select your biological sex
Click "Calculate" to see your eGFR and CKD stage

Frequently Asked Questions

eGFR (using CKD-EPI) and creatinine clearance (using Cockcroft-Gault) both estimate kidney function but use different formulas. eGFR is preferred for CKD diagnosis and staging, while creatinine clearance is often used for drug dosing. CKD-EPI is more accurate across a wider range of kidney function, especially at higher GFR values.

The NKF and ASN task force recommended removing race from eGFR equations in 2021. Using race perpetuated health disparities and had no biological basis - the differences attributed to race were likely due to social determinants of health. The new race-free CKD-EPI 2021 equation is now the recommended standard.

Creatinine levels can be affected by: muscle mass (higher in muscular individuals), diet (high protein or creatine supplements), recent intense exercise, certain medications (trimethoprim, cimetidine), and hydration status. These factors can make eGFR less accurate in some individuals. Cystatin C-based equations may be used when creatinine is unreliable.

Chronic Kidney Disease (CKD) is diagnosed when eGFR is below 60 mL/min/1.73m² OR when there's evidence of kidney damage (like albuminuria) for 3 or more months. CKD is staged G1-G5 based on eGFR, and A1-A3 based on albuminuria. Both values together determine prognosis and treatment approach.

In some cases, yes. Acute kidney injury (AKI) is often reversible. For CKD, while damage is typically permanent, progression can be slowed or stopped with proper management: blood pressure control, diabetes management, avoiding nephrotoxins, and sometimes specific medications like SGLT2 inhibitors or ACE inhibitors. Early detection and treatment are key.

The CKD-EPI equation was developed and validated in adults (18+). Children have different muscle mass, body composition, and creatinine production rates, requiring pediatric-specific equations like the Schwartz formula. If you need to assess kidney function in a child, consult a pediatric nephrologist.

Calculator Limitations

Adults only: Not validated for patients under 18 years
Creatinine-based: May be inaccurate in extremes of muscle mass, amputees, or with high protein intake
Single measurement: CKD diagnosis requires abnormalities present for ≥3 months
Steady state: Assumes stable creatinine; not accurate in acute kidney injury
No cystatin C: Combined creatinine-cystatin C equations may be more accurate in some patients

Medical Disclaimer: This calculator provides an estimate only and should not replace professional medical evaluation. CKD diagnosis requires confirmation with repeat testing and assessment of albuminuria. Always consult your healthcare provider for interpretation and management.