Estimate kidney function (eGFR) from serum creatinine, age, and sex. Uses the 2021 CKD-EPI equation (race-free). Maps to CKD stages 1-5.
Examples use the race-free CKD-EPI 2021 equation and show the corresponding chronic kidney disease stage.
| Profile | Serum creatinine | eGFR (mL/min/1.73m²) | CKD stage |
|---|---|---|---|
| F, age 30 | 0.8 mg/dL | 98 | Stage 1 (normal) |
| M, age 60 | 1.0 mg/dL | 79 | Stage 2 |
| M, age 65 | 1.4 mg/dL | 53 | Stage 3a |
| F, age 70 | 1.8 mg/dL | 32 | Stage 3b |
| M, age 75 | 2.5 mg/dL | 24 | Stage 4 |
| M, age 80 | 4.5 mg/dL | 12 | Stage 5 (kidney failure) |
CKD-EPI 2021 (race-free equation). KDIGO 2012 staging. NKF.
An estimated GFR (eGFR) calculator estimates kidney function from a serum creatinine blood test result. GFR (glomerular filtration rate) measures how well your kidneys filter waste. Our GFR calculator uses the 2021 CKD-EPI creatinine equation, the current standard endorsed by the National Kidney Foundation and American Society of Nephrology. It works for any adult by entering creatinine (mg/dL or µmol/L), age, and sex assigned at birth. The result is matched to the five CKD stages from normal (≥90) to kidney failure (<15).
Normal: 0.6–1.2 mg/dL (53–106 µmol/L)
Estimated GFR
68.6 mL/min/1.73 m²
| Stage | GFR range | Description |
|---|---|---|
| 1 | ≥ 90 | Normal or high |
| 2 | 60-89 | Mildly decreased |
| 3 | 45-59 | Mild to moderately decreased (3a: 45-59; 3b: 30-44) |
| 4 | 15-29 | Moderately to severely decreased |
| 5 | < 15 | Severely decreased (kidney failure if dialysis-dependent) |
Uses the 2021 CKD-EPI creatinine equation (race-free). Source: Inker LA et al. NEJM 2021;385:1737. For medical decisions (medication dosing, referral, dialysis planning), use measured GFR or consult a nephrologist. This calculator is educational.
Calculator output is for informational use only and is not a substitute for clinician interpretation of laboratory results.
Cross-checked against authoritative formulas (IRS, NIST, ACSM) and updated for 2025/2026 tax years and rates.
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Each calculator includes the formula, plain-English explanation, and FAQs so you understand the result.
Estimates only. Calculator results are for educational and planning purposes — not professional advice. For binding decisions on taxes, investments, health, or legal matters, consult a qualified professional.
FAQ
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An estimated GFR (eGFR) calculator is a free kidney-function screening tool that estimates how well your kidneys filter waste. Our GFR calculator uses the 2021 CKD-EPI creatinine equation (race-free, current NKF/ASN standard) from a serum creatinine blood test, age, and sex. The eGFR result maps to the five Chronic Kidney Disease (CKD) stages from normal (≥90) to kidney failure (<15).
How it works
Our GFR calculator uses the 2021 CKD-EPI creatinine equation (race-free, NKF/ASN standard) to estimate kidney function from a single blood test.
Type the creatinine value from your blood test in mg/dL (US) or µmol/L (most other countries). The GFR calculator converts automatically. Normal creatinine is 0.6-1.2 mg/dL.
Type your age and pick the sex assigned at birth. The CKD-EPI equation uses both — age and sex affect the result. The 2021 version does not ask for race.
The GFR calculator shows your estimated GFR (mL/min/1.73 m²) and the corresponding CKD stage (1-5). Each stage is described in a reference table. For medical decisions, consult a nephrologist and use the trend across multiple tests, not a single value.