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CalcSpectrum

GFR Calculator

Estimate your Glomerular Filtration Rate (eGFR) using the race-free 2021 CKD-EPI creatinine equation. Enter serum creatinine (mg/dL), age, and biological sex — adults 18 and older.

Free to use · Instant results

Calculator Inputs

Standardized serum creatinine in mg/dL, from a recent lab result.

This equation applies to adults age 18 and older only.

Used only as a formula input variable per the CKD-EPI equation. This equation does not use a race coefficient.

Estimated GFR
97.58
Units
mL/min/1.73m²
Equation / Version
2021 CKD-EPI Creatinine Equation (race-free)
Your spreadsheet is generated in your browser.

About these results

CalcSpectrum calculators produce automated estimates using established formulas and the specific values you enter. Because real-world outcomes depend on input accuracy, mathematical assumptions, and rounding conventions, please verify critical figures with an appropriately qualified financial, tax, medical, legal, or other professional, as relevant.

Health & Fitness Notice: Wellness and body metric calculations provide informational estimates based on generalized population formulas. They do not provide medical diagnosis, clinical advice, or treatment plans. Consult an appropriately qualified medical or healthcare professional for personal guidance.

How It's Calculated

Formula

eGFR=142×min⁡(Scr/k,1)α×max⁡(Scr/k,1)−1.200×0.9938Age×sex factor\text{eGFR} = 142 \times \min(S_{cr}/k, 1)^{\alpha} \times \max(S_{cr}/k, 1)^{-1.200} \times 0.9938^{\text{Age}} \times \text{sex factor}

This calculator estimates Glomerular Filtration Rate (eGFR) using the 2021 CKD-EPI creatinine equation, the race-free version currently recommended by NIDDK/NKF guidance for adults. It replaces the earlier 2009 CKD-EPI equation, which included a race coefficient now considered outdated. Serum creatinine (k = 0.7 for women, 0.9 for men), age, and biological sex are combined with fixed published constants to produce an eGFR in mL/min/1.73m². This is an estimate for general informational and educational purposes, based on a published formula — it is not a medical diagnosis, and it is not a substitute for individualized advice from a qualified healthcare provider. This tool reports the eGFR number and equation version only — it does not classify chronic kidney disease (CKD) stage, does not diagnose kidney disease, and is not a substitute for a clinician's interpretation of your lab results in the context of your full medical history. This equation applies to adults age 18 and older.

Worked Examples

Male, age 50, serum creatinine 1.0 mg/dL

  1. Scr/k = 1.0 / 0.9 = 1.111 (above 1, so the high-ratio exponent branch applies)
  2. eGFR = 142 x 1^-0.302 x 1.111^-1.200 x 0.9938^50 x 1.0 ≈ 91.7 mL/min/1.73m²

Female, age 50, serum creatinine 1.0 mg/dL

  1. Scr/k = 1.0 / 0.7 = 1.429 (above 1, high-ratio branch)
  2. eGFR = 142 x 1^-0.241 x 1.429^-1.200 x 0.9938^50 x 1.012 ≈ 68.6 mL/min/1.73m²

Frequently Asked Questions

Why is there no race input?

This calculator uses the 2021 CKD-EPI creatinine equation, which NIDDK/NKF guidance currently recommends as the race-free standard for adult eGFR estimation. It replaces the earlier 2009 equation that used a race coefficient.

Does this tell me what CKD stage I'm in?

No. This calculator reports the eGFR number, the equation version, and units only. Chronic kidney disease staging depends on more than a single eGFR value and should be interpreted by a qualified healthcare provider.

Can I use this if I'm under 18?

No. The 2021 CKD-EPI creatinine equation used here applies to adults age 18 and older; this calculator does not accept ages below 18.

What units does serum creatinine need to be in?

mg/dL. If your lab result is reported in µmol/L, convert it first (mg/dL = µmol/L / 88.4) before entering it here.