GFR Calculator — eGFR (CKD-EPI 2021, Race-Free)
Calculate estimated glomerular filtration rate (eGFR) from serum creatinine, age and sex using the 2021 CKD-EPI race-free equation — the standard recommended by KDIGO and the NKF since 2021. The result is mapped to a KDIGO chronic kidney disease stage (G1–G5).
mg/dL
years
Sex (assigned at birth)
CKD-EPI 2021 (race-free) — Inker et al., NEJM 2021
- 1
Creatinine ratio (Scr ÷ κ)
1 ÷ 0.9 = 1.1111κ = 0.7 for female, 0.9 for male — the sex-specific creatinine threshold. - 2
Low-ratio term: min(ratio, 1)^α
1^(-0.302) = 1 - 3
High-ratio term: max(ratio, 1)^(−1.200)
1.1111^(−1.200) = 0.8812 - 4
Age factor: 0.9938^Age
0.9938^45 = 0.7559 - 5
eGFR = 142 × factors
142 × 1 × 0.8812 × 0.7559 = 94.6
How does this calculator work?
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^(−1.200) × 0.9938^Age [× 1.012 if female], using the 2021 race-free CKD-EPI equation. κ = 0.7 (F) / 0.9 (M); α = −0.241 (F) / −0.302 (M). Results are mapped to KDIGO stages G1 (≥90) through G5 (<15 mL/min/1.73 m²). For informational use only.
Formula
How this is calculated
The glomerular filtration rate (GFR) measures how well the kidneys filter waste from the blood, expressed in mL per minute per 1.73 m² of body surface area. Because directly measuring GFR requires infusing a filtration marker (e.g. inulin), clinical practice uses serum creatinine — a muscle-waste product cleared mainly by filtration — to estimate GFR with validated equations.
The 2021 CKD-EPI formula, published by Inker et al. in the New England Journal of Medicine (2021), removed race as a variable after studies showed the race coefficient did not reflect actual biological differences between individuals and introduced inequitable treatment disparities. The formula uses serum creatinine (mg/dL), age (years) and sex assigned at birth. It is the current standard recommended by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines and the National Kidney Foundation.
The result is mapped to KDIGO CKD stages G1 (eGFR ≥ 90, normal/high) through G5 (eGFR < 15, kidney failure). Note that a single eGFR value does not diagnose CKD — the KDIGO definition requires persistently low GFR and/or other kidney damage markers for more than three months. This calculator is for educational and informational use; all clinical decisions should be made with a qualified clinician. To convert serum creatinine from µmol/L to mg/dL, divide by 88.4.
Frequently asked questions
An eGFR of 90 mL/min/1.73 m² or above is classified as CKD Stage G1 (normal or high). In healthy young adults eGFR is commonly 100–130; it declines gradually with age at roughly 0.5–1 mL/min/year after age 40, so values of 60–89 in older adults may reflect normal ageing rather than disease.
Men typically have greater muscle mass than women, producing more creatinine, so the same serum creatinine corresponds to a higher GFR in men. The CKD-EPI formula corrects for this through sex-specific exponents (α) and threshold values (κ), with an additional 1.012 multiplier for female sex.
Divide the µmol/L value by 88.4 to get mg/dL. For example, 88 µmol/L ÷ 88.4 ≈ 1.0 mg/dL. Most hospital lab reports outside the United States report in µmol/L.
Also known as
TG we-Calculate Editorial Team. (2026). GFR Calculator — eGFR (CKD-EPI 2021, Race-Free) [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/glomerular-filtration-rate-calculator
TG we-Calculate Editorial Team. "GFR Calculator — eGFR (CKD-EPI 2021, Race-Free)." TG we-Calculate. 2026. https://we-calculate.com/calculator/glomerular-filtration-rate-calculator.
TG we-Calculate Editorial Team, "GFR Calculator — eGFR (CKD-EPI 2021, Race-Free)," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/glomerular-filtration-rate-calculator
@misc{wecalculate_glomerular_filtration_rate_calculator, title = {GFR Calculator — eGFR (CKD-EPI 2021, Race-Free)}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/glomerular-filtration-rate-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?