Kidney Failure Risk Calculator (KFRE)
Estimate the 2-year and 5-year probability of kidney failure (needing dialysis or a kidney transplant) with the validated 4-variable Kidney Failure Risk Equation — from age, sex, eGFR and urine albumin-to-creatinine ratio (ACR). Free, private (runs 100% in your browser), no sign-up.
Calculate your risk estimate
Enter the four values from your lab report or doctor's note. All fields are required.
Your estimated kidney failure risk
Based on the 4-variable KFRE (Tangri et al., North American calibration). These are statistical estimates for people with similar values — not a prediction about you personally.
2-year risk
5-year risk
What your result means
Clinicians often group KFRE results into three bands to guide planning (KDIGO 2024; NICE 2021). These are population-based planning thresholds — not diagnoses.
| Horizon | Low | Intermediate | High |
|---|---|---|---|
| 2-year risk | < 3% | 3% – 10% | > 10% |
| 5-year risk | < 5% | 5% – 15% | ≥ 15% |
How guidelines use these numbers
- 5-year risk above 5% is a commonly used threshold for referral to a nephrologist (kidney specialist).
- 2-year risk above 10% is used to time preparation discussions: education about treatment options, transplant evaluation, and planning dialysis access.
- Below these thresholds, many people can continue to be monitored in primary care with regular eGFR and ACR checks.
If your estimate falls in an intermediate or high band, consider it a prompt to talk with your doctor — not a verdict.
About the four inputs
Age
Risk rises with age in the general population, but within the KFRE a younger age at the same eGFR and ACR slightly increases the estimated risk of progression — younger patients have more years ahead in which kidney failure can occur, and competing risks are lower.
Sex
Male sex carries a slightly higher estimated risk than female sex at identical lab values, reflecting the derivation data.
eGFR (mL/min/1.73m²)
Estimated glomerular filtration rate — how well your kidneys filter blood. Lower eGFR is the strongest driver of the estimate. CKD stages: G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15. The KFRE was developed for stages G3–G5.
Urine ACR (albumin-to-creatinine ratio)
How much albumin (a protein) leaks into urine — a marker of kidney damage. Higher ACR raises the estimate. KDIGO categories: A1 (normal to mildly increased) below 30 mg/g, A2 (moderately increased) 30–300 mg/g, A3 (severely increased) above 300 mg/g. Enter it in mg/g or mg/mmol; mg/mmol values are multiplied by 8.84 automatically.
The formula (for transparency)
Exactly as published by Tangri et al. — no hidden adjustments. This calculator uses the North American calibration (the default of the official kidneyfailurerisk.com calculator).
LP = −0.2201 × (age/10 − 7.036)
+ 0.2467 × (male − 0.5642)
− 0.5567 × (eGFR/5 − 7.222)
+ 0.4510 × (ln(ACR in mg/g) − 5.137)
2-year risk = 1 − 0.9750 ^ exp(LP)
5-year risk = 1 − 0.9240 ^ exp(LP)| Coefficient | Variable | Effect |
|---|---|---|
| −0.2201 | Age, per 10 years | Slightly lowers the linear predictor per decade |
| +0.2467 | Male sex (1 = male, 0 = female) | Raises estimated risk for men |
| −0.5567 | eGFR, per 5 mL/min/1.73m² | Strongly lowers risk as kidney function rises |
| +0.4510 | ln(ACR in mg/g) | Raises risk as albuminuria rises |
Sources
- Tangri N, Stevens LA, Griffith J, et al. A predictive model for progression of chronic kidney disease to kidney failure. JAMA. 2011;305(15):1553-1559. (derivation)
- Tangri N, Grams ME, Levey AS, et al. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis. JAMA. 2016;315(2):164-174. (validation in 721,357 people, 31 cohorts)
- Kidney Disease: Improving Global Outcomes (KDIGO) 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease — endorses KFRE for risk stratification in CKD G3–G5.
- Coefficients cross-checked against the CDC Stacks supplement of Chu et al. (AJKD) citing Tangri 2016, and against the peer-reviewed open-source implementation by Shpaner (SoftwareX 2026), which reproduces the published reference outputs exactly.
Frequently asked questions
What is the Kidney Failure Risk Equation (KFRE)?
The Kidney Failure Risk Equation (KFRE) is a validated risk model developed by Tangri and colleagues (JAMA 2011) and validated in over 700,000 people across 30+ countries (JAMA 2016). The 4-variable version estimates the probability that a person with chronic kidney disease (CKD) will develop kidney failure — defined as needing dialysis or a kidney transplant — within 2 years and within 5 years, using age, sex, eGFR and the urine albumin-to-creatinine ratio (ACR). It is endorsed by the KDIGO 2024 CKD guideline as the preferred risk-stratification tool for CKD stages G3–G5.
Which four inputs does this KFRE calculator need?
Age in years (18–100), sex (male or female), eGFR in mL/min/1.73m² (from your lab report, usually calculated with the CKD-EPI equation), and the urine albumin-to-creatinine ratio (ACR), which you can enter in mg/g or mg/mmol — the calculator converts mg/mmol to mg/g automatically by multiplying by 8.84.
How are the 2-year and 5-year risks calculated?
The calculator computes a linear predictor LP = −0.2201×(age/10 − 7.036) + 0.2467×(male − 0.5642) − 0.5567×(eGFR/5 − 7.222) + 0.4510×(ln(ACR) − 5.137), where male is 1 for men and 0 for women and ACR is in mg/g. The 2-year risk is 1 − 0.9750^exp(LP) and the 5-year risk is 1 − 0.9240^exp(LP). These are the published North American calibration coefficients from Tangri et al.
Should I enter ACR in mg/g or mg/mmol?
Either — the equation itself uses mg/g, but this calculator accepts both and converts automatically. To convert mg/mmol to mg/g, multiply by 8.84 (based on creatinine's molecular weight of 113.12 g/mol). For reference, KDIGO albuminuria categories are: A1 (normal to mildly increased) below 30 mg/g, A2 (moderately increased) 30–300 mg/g, and A3 (severely increased) above 300 mg/g.
What do low, intermediate and high risk mean?
For the 2-year horizon: below 3% is considered low risk, 3–10% intermediate, and above 10% high — guidelines suggest a 2-year risk above 10% should prompt discussion of timely preparation for kidney replacement therapy with a nephrologist. For the 5-year horizon: below 5% is low, 5–15% intermediate, and 15% or above high — a 5-year risk above 5% is a commonly used threshold for nephrology referral (KDIGO 2024, NICE 2021). These are population-based planning thresholds, not diagnoses.
Who was the KFRE developed and validated in?
The equation was developed in 3,449 Canadian patients with CKD stages 3–5 referred for nephrology care (Tangri et al., JAMA 2011) and later validated in 721,357 participants with CKD stages 3–5 across 31 cohorts in more than 30 countries (Tangri et al., JAMA 2016), with excellent discrimination (C-statistic ~0.90 at 2 years). This calculator uses the original North American calibration, which is also the default of the official kidneyfailurerisk.com calculator.
Can this calculator diagnose kidney failure or CKD?
No. It provides an educational statistical estimate based on four variables — it cannot diagnose kidney disease, stage your CKD, or predict your personal outcome. Kidney failure risk also depends on factors the equation does not include, such as blood pressure control, diabetes, medications and other illnesses. Always discuss your results with your nephrologist or doctor.
How is this different from an eGFR calculator?
An eGFR calculator estimates your current kidney filtering function from a blood creatinine value — it describes where your kidneys are today. The KFRE does the opposite: it takes an existing eGFR (plus age, sex and ACR) and estimates the future probability of progressing to kidney failure. This tool does not compute eGFR; you enter the eGFR from your lab report.
What are the limitations of the KFRE?
The KFRE was developed for adults with CKD stages G3–G5 and is less applicable outside that range. It treats death before kidney failure as a censoring event, so it can overestimate risk in very elderly patients who have a high competing risk of death. It uses a single set of measurements — trends over time also matter. It does not apply to acute kidney injury. Calibration outside North America may differ; the multinational validation found the original equation overestimated risk in some non-North-American cohorts.
My estimated risk is high — what should I do?
Treat the number as a prompt for conversation, not a verdict. Guidelines suggest discussing a 5-year risk above 5% with your doctor about a nephrology referral, and a 2-year risk above 10% about timely planning (education, transplant evaluation, dialysis access) with a nephrologist. Do not start, stop or change any medication or diet based on this estimate — bring the result to your next appointment.
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