Free Kidney Failure Risk Calculator

Renal Failure Risk Assessment with the KFRE Calculator

The Kidney Failure Risk Calculator (also known as the KFRE Calculator) is a free online tool for kidney disease risk assessment. It computes your 5‑year kidney failure probability using validated clinical parameters and provides an evidence‑based estimate of disease progression. This renal failure risk calculator integrates the Kidney Failure Risk Equation to help patients and clinicians understand the likelihood of reaching end‑stage renal disease within five years.

Important: This tool is intended for educational and informational purposes only. It does not replace professional medical advice. Always consult a nephrologist or healthcare provider for personalized diagnosis and treatment.

What Is Kidney Failure?

Kidney (renal) failure represents the most advanced stage of kidney insufficiency, at which the organs can no longer adequately filter waste or regulate fluid and electrolyte balance. The decline may occur rapidly (acute kidney injury) or take many years (chronic kidney disease). Common symptoms of advanced kidney failure include:

• Dry, itchy, and darkened skin
• Swelling in the legs, ankles, or face (edema)
• Shortness of breath due to fluid accumulation around the lungs
• Muscle cramps and fatigue
• Nausea, vomiting, and unintended weight loss

When kidney function drops below a critical threshold, renal replacement therapy becomes necessary to sustain life. Standard in‑center hemodialysis is typically scheduled three or four times per week, with each session lasting about four to five hours. Peritoneal dialysis offers a home‑based alternative, especially for pediatric patients.

Risk Factors for Kidney Failure

Several conditions and lifestyle factors raise the risk of developing renal failure. These include:

• Hypertension (high blood pressure)
• Diabetes mellitus (especially when poorly controlled)
• Obesity
• Smoking
• High-protein diet (may accelerate existing kidney damage)
• Cardiovascular diseases
• Congenital kidney malformations
• Family history of kidney disease

Early identification of these risk factors can help slow progression and delay the onset of end‑stage renal disease.

How the Kidney Failure Risk Equation (KFRE) Works

The KFRE calculator uses a scoring system based on eight clinical variables: age, sex, urine albumin‑to‑creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), serum albumin, serum bicarbonate, serum calcium, and serum phosphorus. For each variable, points are assigned according to the patient’s measurement. These points are summed to obtain a total score. That total score is then mapped to a 5‑year probability of kidney failure.

Variable Descriptions and Point Tables

Each variable contributes specific points. A more negative score generally indicates higher risk.

Age

Age (years)	Points
< 30	-4
30–39	-2
40–49	0
50–59	2
60–69	4
70–79	6
80–89	8
≥ 90	10

Sex

Sex	Points
Female	0
Male	-2

Urine Albumin‑to‑Creatinine Ratio (ACR)

ACR reflects protein leakage through the kidney filters. High values signal glomerular damage.

ACR (mg/g)	Points
< 30	0
30–300	-14
> 300	-22

Estimated Glomerular Filtration Rate (eGFR)

eGFR is the primary indicator of kidney filtration capacity. Lower eGFR corresponds to worse kidney function.

eGFR (mL/min/1.73 m²)	Points
< 15	-35
15–19	-30
20–24	-25
25–29	-20
30–34	-15
35–39	-10
40–44	-5
45–49	0
50–54	5
> 54	10

Serum Albumin

Low albumin indicates protein loss and is a marker of malnutrition or chronic disease.

Serum Albumin (g/dL)	Points
≤ 2.5	-5
2.6–3.0	0
3.1–3.5	2
≥ 3.6	4

Serum Bicarbonate (HCO₃⁻)

Bicarbonate reflects acid‑base balance. Very low levels suggest metabolic acidosis, common in advanced kidney disease.

Serum Bicarbonate (mEq/L)	Points
< 18	-7
18–22	-4
23–25	-1
> 25	0

Serum Calcium

Serum Calcium (mg/dL)	Points
≤ 8.5	-3
8.6–9.5	0
≥ 9.6	2

Serum Phosphorus

Phosphorus tends to rise as kidney function declines, contributing to vascular calcification.

Serum Phosphorus (mg/dL)	Points
< 3.5	3
3.5–4.5	0
4.6–5.5	-3
> 5.5	-5

Converting Total Score to 5‑Year Kidney Failure Probability

Once you have summed all points, locate your total score in the left column of the conversion table. The corresponding value in the right column is the estimated probability (percentage) of developing kidney failure within five years.

Total Score	5‑Year Probability
< -41	> 90.0%
-41	89.0%
-40	86.9%
-39	84.1%
-38	81.0%
-37	81.0%
-36	74.4%
-35	70.9%
-34	67.3%
-33	63.6%
-32	59.9%
-31	56.3%
-30	52.8%
-29	49.3%
-28	45.9%
-27	42.7%
-26	39.6%
-25	36.6%
-24	33.8%
-23	31.2%
-22	28.7%
-21	26.4%
-20	24.2%
-19	22.2%
-18	20.3%
-17	18.6%
-16	17.0%
-15	15.5%
-14	14.1%
-13	12.9%
-12	11.7%
-11	10.7%
-10	9.7%
-9	8.8%
-8	8.0%
-7	7.3%
-6	6.6%
-5	6.0%
-4	5.5%
≥ -3	< 5.0%

Note: A probability of, say, 50 % means that, statistically, 1 out of 2 individuals with the same total score will experience kidney failure within the next five years. This is a population‑based estimate and cannot predict individual timing or the exact year of progression.

Using the Score to Guide Decisions

Clinicians often use the KFRE to identify patients who would benefit most from nephrology referral, preparation for dialysis, or pre‑emptive kidney transplantation. The equation is particularly well validated in patients with stage 3–5 chronic kidney disease (eGFR < 60 mL/min/1.73 m²). Remember that the KFRE is one of several tools; the actual course of kidney disease may be influenced by medication adherence, diet, and comorbid conditions. The calculator should be used in combination with clinical judgment and not as a standalone decision‑making device.