Calculate estimated glomerular filtration rate using the CKD-EPI 2021 race-free equation. Determine chronic kidney disease stage and kidney function.
The eGFR Calculator estimates glomerular filtration rate from serum creatinine, age, and sex using the CKD-EPI 2021 race-free creatinine equation. It is a quick way to translate a creatinine result into the standardized mL/min/1.73 m² value commonly used in kidney-function reporting.
This page is most useful for reviewing where a creatinine result falls in the usual kidney-function bands and for understanding how age and sex affect the estimate. It uses the current race-free equation rather than older formulas that included a race coefficient.
The result is only one part of kidney assessment. eGFR by itself does not complete CKD staging without urine albumin data, and the estimate can be less reliable in acute kidney injury, very unusual muscle mass, pregnancy, and some other clinical settings.
Creatinine alone is hard to interpret without context. This page converts it into the standard CKD-EPI 2021 estimate, keeps the stage bands visible, and makes it easier to review whether the result is broadly normal, mildly reduced, or clearly in an advanced CKD range.
CKD-EPI 2021 Race-Free Equation: Female: • If Scr ≤ 0.7: eGFR = 142 × (Scr/0.7)^(−0.241) × 0.9938^age • If Scr > 0.7: eGFR = 142 × (Scr/0.7)^(−1.200) × 0.9938^age Male: • If Scr ≤ 0.9: eGFR = 142 × (Scr/0.9)^(−0.302) × 0.9938^age • If Scr > 0.9: eGFR = 142 × (Scr/0.9)^(−1.200) × 0.9938^age CKD Stages: • Stage 1: GFR ≥ 90 (Normal) • Stage 2: 60–89 (Mildly decreased) • Stage 3a: 45–59 (Mild-moderate) • Stage 3b: 30–44 (Moderate-severe) • Stage 4: 15–29 (Severely decreased) • Stage 5: < 15 (Kidney failure)
Result: eGFR = 71 mL/min/1.73m² — Stage 2 (Mildly Decreased)
Using the CKD-EPI 2021 male equation with Scr = 1.2 mg/dL (>0.9): eGFR = 142 × (1.2/0.9)^(−1.200) × 0.9938^55 ≈ 71.4, which rounds to 71 mL/min/1.73m². That falls in the stage 2 range. CKD staging still depends on whether the reduction is persistent and whether albuminuria or other kidney abnormalities are present.
The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) published the race-free equation in 2021, endorsed by the NKF and ASN. It replaced the 2009 CKD-EPI equation that used a race coefficient, and has become the recommended standard worldwide. The equation was developed from a large, diverse population and validated across multiple cohorts.
CKD staging combines eGFR with albuminuria (protein in urine) to create a risk matrix. An eGFR of 55 with normal urine protein (stage 2) has a much better prognosis than an eGFR of 55 with heavy proteinuria (high risk for progression). Both values should be assessed together for comprehensive kidney health evaluation.
Referral is recommended for: eGFR below 30 (stage 4–5), persistent eGFR decline >5/year, significant proteinuria (urine albumin-to-creatinine ratio >300), resistant hypertension with reduced eGFR, or unexplained kidney function abnormalities. Early nephrology involvement improves outcomes and preparation for renal replacement therapy if needed.
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This page applies the CKD-EPI 2021 race-free creatinine equation using age, sex, and serum creatinine in mg/dL, then reports the result as eGFR in mL/min/1.73 m². It also groups the estimate into the usual G-stage bands so the number can be reviewed in the same staging language used in kidney-function reporting.
The result is intended as a kidney-function estimate rather than a complete CKD diagnosis. Chronic kidney disease staging also depends on persistence over time and albuminuria, and creatinine-based estimates can be less reliable in acute kidney injury, pregnancy, unusual muscle mass, and other settings where creatinine generation or steady-state assumptions are altered.
eGFR (estimated glomerular filtration rate) estimates how much blood your kidneys filter per minute, normalized to body surface area. Normal eGFR is 90–120 mL/min/1.73m². Below 60 for more than 3 months defines chronic kidney disease. It's calculated from serum creatinine, age, and sex.
The NKF and ASN task force determined that race-based adjustments were problematic: race is a social construct, not a biological variable. The adjusted coefficients had led to underdiagnosis of kidney disease in Black patients. The 2021 CKD-EPI equation uses a single formula for all patients.
Dialysis is typically considered in Stage 5 (eGFR < 15), though the decision depends on symptoms, not just the number. Some patients start dialysis at eGFR 5–10 when they develop symptoms like fluid overload, nausea, or hyperkalemia. Pre-emptive kidney transplant is preferred when available.
eGFR can improve if the underlying cause is treated: controlling blood pressure, managing diabetes, stopping nephrotoxic drugs, or relieving urinary obstruction. However, most CKD represents permanent nephron loss and is progressive. The goal is usually to slow decline rather than reverse it.
eGFR can overestimate kidney function in elderly patients with low muscle mass (less creatinine production). Cystatin C-based equations may be more accurate in this population. An eGFR of 50 in an 85-year-old may reflect age-related decline rather than disease.
Many medications require dose adjustment when eGFR drops below 60, including antibiotics (aminoglycosides, vancomycin), diabetes drugs (metformin below 30), contrast agents, and opioids. Always inform your pharmacist and doctors about your eGFR so they can adjust doses appropriately.