A walkthrough, end to end.
- 1
Enter your serum creatinine (from your most recent lab), age, and sex.
- 2
The calculator runs the 2021 CKD-EPI race-free equation, the current ASN/NKF standard.
- 3
Read your eGFR and the corresponding CKD stage. Persistently low eGFR (<60 for >3 months) defines chronic kidney disease.
CKD-EPI 2021 (race-free)
Adopted by the National Kidney Foundation and American Society of Nephrology in 2021 to remove the race coefficient from the prior CKD-EPI equation. Uses creatinine, age, and sex only.
What you can do with this.
CKD staging
G1 ≥90 (with kidney damage marker), G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15. Staging combines eGFR + albuminuria (KDIGO 2012).
Drug-dosing decisions
Many medications (e.g., metformin, DOACs, gadolinium contrast) have eGFR cutoffs. Your provider/pharmacist will use the same formula to adjust doses.
Race-free equation context
The 2021 race-free equation gives slightly lower eGFR for people previously assessed as Black, leading to earlier CKD detection. ASN/NKF formally endorsed this in 2021.
Tracking eGFR trend over time
A single low eGFR doesn't mean CKD — confirmation requires persistence over 3+ months. Track quarterly; an annual decline >5 mL/min/yr warrants a nephrology consult.
eGFR in pregnancy
GFR rises 40–50% during pregnancy due to expanded plasma volume. Standard CKD-EPI underestimates true GFR in pregnancy; specialized formulas exist but the calculator here uses the non-pregnant equation.
Diet protein and eGFR
Very high protein intake (>2.2 g/kg) transiently raises GFR via hyperfiltration. For healthy kidneys this is benign; for established CKD, protein is often moderated to 0.6–0.8 g/kg under medical supervision.
Hydration's effect on creatinine
Dehydration concentrates creatinine and lowers eGFR readings. For accurate trend tracking, get fasting morning labs after normal hydration — repeating them on a hot, dehydrated day distorts comparison.
GFR for kidney donors
Living kidney donors must have eGFR ≥90 (often higher) and other markers. The calculator gives your starting point; donor evaluation includes 24-hour urine, imaging, and specialist review.
GFR calculator 2026 — what's current
Cystatin C-based eGFR is increasingly recommended (KDIGO 2024) when accuracy matters — drug dosing in muscular patients, transplant assessment, donor evaluation. Combined Cr+CysC eGFR is the new gold standard.
Frequently asked.
≥90 mL/min/1.73 m² is normal for healthy adults; eGFR declines naturally with age (~1 mL/min/year after 30).
Cystatin C (or combined Cr+CysC) is more accurate, especially at higher GFRs and in muscular individuals. Many labs now offer it; it's preferred when creatinine-based estimates seem off.
The race coefficient assumed Black patients had higher creatinine generation, leading to falsely-elevated eGFR estimates and later CKD diagnoses. The 2021 equation removes this.
No. eGFR is one piece of a kidney workup. Discuss interpretation with your clinician.
mGFR uses iohexol or iothalamate clearance — direct measurement, gold standard, but expensive and rarely needed clinically. eGFR is the calculation-based estimate from blood creatinine; sufficient for nearly all clinical decisions.
Some causes are reversible (dehydration, medication effects, acute injury). Chronic kidney disease is generally not reversed but can be slowed — blood pressure control, diabetes management, and avoiding nephrotoxins matter most.
No. The calculation runs entirely in your browser. Nothing is sent to a server, no analytics on inputs, no cookies.