UKMedCalc

For healthcare professionals. Educational tool only — not a medical device. Verify all results against the current BNF, NICE guidance and local policy, and apply clinical judgement.

Renal

eGFR — CKD-EPI 2021 (race-free creatinine)

Estimates GFR using the 2021 CKD-EPI creatinine equation, refitted without a race coefficient (ASN/NKF recommendation in the US).

years

The original equations were derived using sex at birth

Steady-state value only — eGFR is unreliable in acute kidney injury

Enter the required values to see the result.

Formula

eGFR=142×min⁡(SCrκ,1)α×max⁡(SCrκ,1)−1.200×0.9938age×1.012  (if female)\text{eGFR} = 142 \times \min\left(\frac{S_{Cr}}{\kappa}, 1\right)^{\alpha} \times \max\left(\frac{S_{Cr}}{\kappa}, 1\right)^{-1.200} \times 0.9938^{\text{age}} \times 1.012 \; \text{(if female)}

κ = 0.7 (female) or 0.9 (male); α = −0.241 (female) or −0.302 (male). Serum creatinine in mg/dL (divide µmol/L by 88.4 — handled automatically). Cystatin C and combined creatinine–cystatin C equations were published alongside.

Caveats & limitations

  • Unreliable in acute kidney injury, pregnancy, and at extremes of muscle mass or diet (e.g. amputees, severe malnutrition, high-meat diets, creatine supplements).
  • The KDIGO G category alone does not diagnose CKD — chronicity (≥3 months) or other markers of kidney damage are required.
  • eGFR is indexed to 1.73 m² body surface area; for drug dosing follow the basis in the BNF/SmPC.
  • Confirmatory testing with cystatin C is recommended when a more accurate estimate would change management.

Evidence & UK guidance

Primary evidence

  • Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med. 2021;385(19):1737–1749.

    PubMedDOI

UK practice

Recommended in the US by ASN/NKF as the race-free standard. NICE NG203 recommends a creatinine-based eGFR reported by UK laboratories (the 2009 CKD-EPI equation in current practice) without an ethnicity adjustment; the 2021 equation has not been fully validated in UK populations. For drug dosing, follow the basis stated in the BNF/SmPC (often Cockcroft–Gault).

Official resources

Formula and citations last verified: 2026-08-03

Related calculators

CKD-EPI 2009 eGFR

Estimates GFR using the original 2009 CKD-EPI creatinine equation — the basis of eGFR reported by UK laboratories.

MDRD eGFR

Estimates GFR using the 4-variable MDRD Study equation re-expressed for standardised (IDMS-traceable) creatinine. Largely superseded by CKD-EPI.

Cockcroft–Gault CrCl

Estimates creatinine clearance for drug dosing from age, sex, weight and serum creatinine, with actual, ideal or adjusted body weight options.