Health & Fitness
Estimate your glomerular filtration rate using the CKD-EPI 2021 equation.
Estimated GFR
94.6 mL/min/1.73m²
CKD Stage G1 — Normal or high
Kidney function normal; monitor for CKD risk factors.
This is an estimate based on serum creatinine. It is not a diagnosis. Consult your doctor for clinical interpretation and to discuss CKD management, medication adjustments, and follow-up testing.
eGFR is a measure of kidney function expressed in mL/min/1.73 m² (millilitres of blood filtered per minute per square metre of body surface area). It's estimated from serum creatinine—a waste product of muscle metabolism—adjusted for age and sex. The CKD-EPI 2021 equation is the current gold standard for non-Black populations and offers a race-neutral formula. eGFR ranges from 90+ (normal) down to below 15 (kidney failure), grouped into five CKD stages (G1–G5).
The calculator applies the CKD-EPI 2021 creatinine equation: eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × (1.012 if female), where Scr is serum creatinine in mg/dL, κ (kappa) is 0.7 for females or 0.9 for males, and α (alpha) is −0.241 for females or −0.302 for males. The result is stratified into CKD stages G1–G5 based on eGFR thresholds (G1: ≥90, G2: 60–89, G3a: 45–59, G3b: 30–44, G4: 15–29, G5: <15).
eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × sex factorScr = serum creatinine (mg/dL); κ = 0.7 (female) or 0.9 (male); α = −0.241 (female) or −0.302 (male); sex factor = 1.012 (female) or 1.0 (male); age in years. The formula accounts for age-related decline and sex differences in creatinine production due to muscle mass differences. The min/max terms handle both high and low creatinine ranges appropriately.
| Input | Result | Notes |
|---|---|---|
| Age 45, male, serum creatinine 1.0 mg/dL | eGFR ≈ 98 mL/min/1.73m² (Stage G1) | Normal kidney function; eGFR ≥ 90 indicates no evidence of kidney disease. Continue healthy habits and monitor for CKD risk factors. |
| Age 65, female, serum creatinine 1.2 mg/dL | eGFR ≈ 51 mL/min/1.73m² (Stage G3a) | Mildly to moderately reduced kidney function; CKD Stage 3a is present. Manage blood pressure and blood sugar; discuss medication adjustments with your doctor. |
| Age 72, male, serum creatinine 3.5 mg/dL | eGFR ≈ 18 mL/min/1.73m² (Stage G4) | Severely reduced kidney function; Stage G4 CKD. Specialist nephrology care is strongly recommended; assess for dialysis or transplant eligibility. |
Serum creatinine is a waste product of muscle metabolism filtered out by your kidneys. Higher serum creatinine suggests the kidneys are filtering less efficiently. It's the cornerstone of eGFR because it's inexpensive, widely measured, and reflects kidney filtration capacity. However, it's influenced by muscle mass, age, sex, and diet, which is why the CKD-EPI formula adjusts for these factors.
Females have less muscle mass on average than males, so they typically produce less creatinine at the same kidney function level. The CKD-EPI equation uses different kappa (κ) and alpha (α) coefficients for males and females to account for this difference, making the estimate more accurate.
CKD Stage G1 (eGFR ≥ 90) indicates normal or high kidney function. There is no evidence of kidney disease. However, if albuminuria or proteinuria is present, CKD may still be diagnosed. Regular monitoring is recommended, especially if you have diabetes or hypertension.
eGFR 60–89 alone does not diagnose CKD. CKD Stage G2 is present only if eGFR 60–89 is accompanied by evidence of kidney damage (e.g., albuminuria, proteinuria, imaging abnormalities, or a kidney disease history). Talk to your doctor about your full clinical picture.
If you have normal kidney function (eGFR ≥ 60) and no CKD risk factors, screening every 1–2 years may suffice. If you have diabetes, hypertension, or known CKD, your doctor may recommend annual or more frequent testing (e.g., every 3–6 months). Acute illness may warrant urgent re-checking.
Yes. eGFR is an estimate, not a measurement of true GFR. It can be inaccurate in people with very high or low muscle mass, vegetarian/vegan diets (lower creatinine), or acute kidney injury (creatinine hasn't yet equilibrated). In these cases, a doctor may order cystatin C, inulin clearance, or other confirmatory tests. Always discuss unexpected results with your healthcare provider.