eGFR Calculator
Estimate kidney function from a creatinine result with the CKD-EPI 2021 equation, and see the CKD stage.
Albumin-to-creatinine ratio, for the albuminuria stage and KDIGO's risk
With height, adds eGFR for your body size, in mL/min
Choose a sex, then enter the creatinine result and the age to see the result.
For drug doses that use Cockcroft-Gault: Creatinine Clearance Calculator.
Turns the creatinine on a blood test report into an estimated glomerular filtration rate (eGFR): how much blood the kidneys filter each minute, scaled to an average body surface of 1.73 m². It uses the race-free CKD-EPI 2021 equation, adds the creatinine–cystatin C version when you have both, and places the result in KDIGO's stages. For ages 1 to 25, the Child & young adult mode uses the CKiD U25 equations instead. Every calculation runs in your browser.
For clinicians it also gives the albuminuria stage and KDIGO's risk colour from a urine albumin-to-creatinine ratio, and the eGFR for the person's own body size for drug dosing.
Understanding the result
eGFR is reported as a whole number, as KDIGO 2024 asks labs to report it, and staged on that number: 59.6 shows as 60 and is G2.
- G1 (≥ 90) — normal or high.
- G2 (60–89) — mildly decreased.
- G3a (45–59) — mildly to moderately decreased.
- G3b (30–44) — moderately to severely decreased.
- G4 (15–29) — severely decreased.
- G5 (< 15) — kidney failure.
A stage on its own is not a diagnosis. Chronic kidney disease needs abnormal results for more than 3 months, and G1 or G2 without other markers of kidney damage, such as albumin in the urine, is not CKD. The estimate is less reliable when kidney function is changing quickly (acute kidney injury), after an amputation, with very high or low muscle mass, and in pregnancy, when the tool gives no result.
With a urine albumin-to-creatinine ratio (ACR), the tool adds the albuminuria stage — A1 below 30 mg/g (3 mg/mmol), A2 up to and including 300 mg/g (30 mg/mmol), A3 above — and the colour KDIGO gives that combination. Each unit is read against its own printed cut-offs, so 3.0 mg/mmol is A2 even though it converts to under 30 mg/g.
How it works
Creatinine in µmol/L is divided by 88.4 to give mg/dL. In CKD-EPI 2021, κ is 0.7 for women and 0.9 for men, and the exponent α is −0.241 for women and −0.302 for men (−0.219 and −0.144 in the cystatin C equation). The equations have no race term.
CKiD U25 multiplies height in metres by a constant that depends on age and sex, divided by creatinine; with cystatin C it also divides a second constant by cystatin C and reports the mean of the two. It takes age with its fraction of a year, from the date of birth and the test date. Bedside Schwartz (2009) is shown beside it to age 17.
With height and weight, eGFR is multiplied by the body surface area (Mosteller) and divided by 1.73 to give mL/min, the form KDIGO advises for drug dosing in very small or large bodies.
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 [if female]
eGFR(cr-cys) = 135 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−0.544 × min(Scys/0.8, 1)^−0.323 × max(Scys/0.8, 1)^−0.778 × 0.9961^age × 0.963 [if female]
CKiD U25: eGFR = K × height (m) ÷ Scr, and K ÷ cystatin C
Bedside Schwartz: eGFR = 0.413 × height (cm) ÷ Scr
BSA (m²) = √(height cm × weight kg ÷ 3600)
Examples
Woman, 60, creatinine 1.1 mg/dL
eGFR 58 mL/min/1.73 m²: G3a, mildly to moderately decreased.
Man, 45, creatinine 97 µmol/L and cystatin C 1.2 mg/L
97 µmol/L is 1.10 mg/dL. Creatinine alone gives 85 (G2); with cystatin C the estimate is 74, which KDIGO 2024 prefers where both are measured.
Man, 60, creatinine 1.2 mg/dL, 178 cm and 95 kg
eGFR 69 mL/min/1.73 m² (G2). For a body surface of 2.17 m², that is 87 mL/min.
Boy aged 12, 150 cm, creatinine 0.6 mg/dL
CKiD U25 gives 98 mL/min/1.73 m², and bedside Schwartz 103.
KDIGO risk by stage
| GFR stage | A1 (normal to mildly increased) | A2 (moderately increased) | A3 (severely increased) |
|---|---|---|---|
| G1 | Low risk | Moderately increased risk | High risk |
| G2 | Low risk | Moderately increased risk | High risk |
| G3a | Moderately increased risk | High risk | Very high risk |
| G3b | High risk | Very high risk | Very high risk |
| G4 | Very high risk | Very high risk | Very high risk |
| G5 | Very high risk | Very high risk | Very high risk |
Rules and sources
The adult equations are Table 2 of Inker et al. (2021), the CKD-EPI refit without race. The stages, the albuminuria categories, the risk grid and whole-number reporting are from the KDIGO 2024 guideline. CKiD U25 is Table 2 of Pierce et al. (2021) for ages 1 to 25, and the bedside Schwartz constant is as NIDDK prints it.
Sources
- Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race (N Engl J Med 2021;385:1737–1749), Table 2 — New England Journal of Medicine
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (Kidney Int 2024;105(4S):S117–S314) — KDIGO
- Pierce CB et al. Age- and sex-dependent clinical equations to estimate glomerular filtration rates in children and young adults with chronic kidney disease (Kidney Int 2021;99:948–956), Table 2 — PubMed Central
- Estimating glomerular filtration rate in children, adolescents and young adults: CKiD U25 and bedside Schwartz — NIDDK, National Institutes of Health
- Mosteller RD. Simplified calculation of body-surface area (N Engl J Med 1987;317:1098) — New England Journal of Medicine
Reviewed
Frequently asked questions
See also
- Creatinine Clearance Calculator — Cockcroft-Gault clearance for drug dosing.
- A1c Calculator & Blood Sugar Converter — HbA1c and blood sugar against the ADA, WHO, NICE or ICMR bands.