Estimated glomerular filtration rate is the number most labs now print under every creatinine result. This calculator uses the same equation they use in the US: the 2021 CKD-EPI creatinine equation, which leaves race out. Enter age, sex and creatinine in either mg/dL or µmol/L and you get the eGFR and its KDIGO category. It replaces the MDRD equation this page used before October 2026.
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eGFR = 142 × min(Scr/κ, 1)α × max(Scr/κ, 1)−1.200 × 0.9938age × 1.012 [if female], with creatinine (Scr) in mg/dL. κ is 0.7 for females and 0.9 for males; α is −0.241 for females and −0.302 for males. The result is in mL/min/1.73 m².
The min and max terms split the curve in two. Below κ, creatinine has only a small effect; above it, every rise in creatinine pulls the eGFR down steeply. That is why a creatinine creeping from 1.0 to 1.4 mg/dL in an older man matters more than the small numbers suggest. Creatinine in µmol/L is divided by 88.4 first, which the calculator does for you.
The equation was built for creatinine measured with IDMS-standardised assays, which almost every lab now uses. It is meant for adults whose creatinine is stable.
The older MDRD and 2009 CKD-EPI equations multiplied the result by a fixed factor for Black patients. That assigned higher kidney function on the basis of a social category rather than anything measured, and it could delay referral, transplant listing and dose changes. In 2021 a joint National Kidney Foundation and American Society of Nephrology task force recommended the refitted CKD-EPI 2021 equation, which has no race term, and labs across the US switched to it. This page made the same change in October 2026. If you compare an old MDRD result with a new CKD-EPI one, expect small differences that reflect the equation, not the kidneys.
| Category | eGFR (mL/min/1.73 m²) | Description |
|---|---|---|
| G1 | 90 or higher | 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 | below 15 | Kidney failure |
A category is not a diagnosis. KDIGO defines chronic kidney disease as abnormal kidney structure or function present for more than 3 months. An eGFR below 60 on two results at least 3 months apart meets that on its own; G1 and G2 count only with another marker of damage, most often albuminuria.
| Category | Urine albumin-to-creatinine ratio | Description |
|---|---|---|
| A1 | below 30 mg/g (below 3 mg/mmol) | Normal to mildly increased |
| A2 | 30–300 mg/g (3–30 mg/mmol) | Moderately increased |
| A3 | above 300 mg/g (above 30 mg/mmol) | Severely increased |
KDIGO stages CKD by both: a patient might be "G3a A2". Risk climbs with each step in either direction, which is why a urine ACR is part of the same work-up as the blood test.
| Patient | Creatinine | eGFR | Category |
|---|---|---|---|
| 45 y, male | 0.9 mg/dL (80 µmol/L) | 107 | G1 |
| 60 y, female | 1.0 mg/dL (88 µmol/L) | 64 | G2 |
| 72 y, male | 1.4 mg/dL (124 µmol/L) | 53 | G3a |
| 80 y, female | 1.6 mg/dL (141 µmol/L) | 32 | G3b |
| 58 y, male | 2.8 mg/dL (248 µmol/L) | 25 | G4 |
| 35 y, female | 0.6 mg/dL (53 µmol/L) | 120 | G1 |
Compare the 60-year-old woman and the 72-year-old man: creatinine of 1.0 against 1.4 mg/dL gives 64 against 53. The 80-year-old woman has a creatinine of 1.6 mg/dL, which looks only modestly raised on a lab sheet, yet her eGFR is 32, one step above G4. Age and sex carry real weight in the equation.
eGFR is scaled to a standard body surface area of 1.73 m², which makes it good for staging and comparing patients. Many drug labels, especially older ones, give renal dose bands in creatinine clearance from the Cockcroft-Gault equation, in plain mL/min. The two can differ by a lot in very small, very large or very old patients. When a drug reference asks for CrCl, use the creatinine clearance calculator, and follow pharmacy guidance on which one applies.
Any creatinine-based estimate fails when creatinine is not in a steady state. In acute kidney injury the creatinine lags behind the actual fall in filtration, so the eGFR looks better than the kidneys are. Very high or very low muscle mass, amputation, and pregnancy also distort it. KDIGO suggests adding cystatin C (eGFRcr-cys) when a more accurate estimate would change a decision.
An eGFR of 90 mL/min/1.73 m² or higher is category G1, and 60–89 is G2. Neither counts as chronic kidney disease unless there is other evidence of kidney damage, such as albumin in the urine. eGFR falls gradually with age, so a value in the 60s is common in older adults.
The 2021 CKD-EPI equation was refitted without a race term after an NKF-ASN task force found that the race coefficient in older equations was not based on a measured biological difference and could delay care. US labs have moved to the race-free equation.
An eGFR below 15 mL/min/1.73 m² is category G5, kidney failure. Planning for dialysis, transplant or conservative care usually starts well before that, and an eGFR below 30 (G4) generally prompts nephrology involvement.
Follow the drug reference. Many labels give renal dose bands in creatinine clearance from Cockcroft-Gault, in mL/min, while eGFR is reported per 1.73 m². In very small, large or elderly patients the two can differ enough to change the dose band, so pharmacy guidance decides which to use.
Not reliably. eGFR equations assume creatinine is stable. In acute kidney injury creatinine rises after filtration has already fallen, so the eGFR overestimates kidney function. AKI is staged by changes in creatinine and urine output instead.