Coronary Calcium (Agatston) Score Calculator
Enter each calcified lesion's area (mm²) and peak attenuation (HU). The calculator applies the standard Agatston density weighting and sums the lesion scores.
| # | Artery | Area (mm²) | Peak HU | Density Factor | Lesion Score | Remove |
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What is the Agatston score?
The Agatston score is a numeric measure of calcified plaque in the coronary arteries, derived from a non-contrast cardiac CT scan (often called a CAC scan). In general, a higher score means a higher burden of coronary atherosclerosis and a higher future risk of cardiovascular events, especially when interpreted together with age, sex, blood pressure, cholesterol, diabetes status, and smoking history.
It is one of the most commonly used ways to quantify coronary artery calcium because it is simple, standardized, and clinically useful for risk stratification.
How Agatston scoring is calculated
Step 1: Identify calcified lesions
On CT, each focus of coronary calcification is measured by area (mm²) and peak density in Hounsfield Units (HU). Lesions below 130 HU are not counted in classic Agatston scoring.
Step 2: Assign density factor
- 130-199 HU → factor 1
- 200-299 HU → factor 2
- 300-399 HU → factor 3
- ≥400 HU → factor 4
Step 3: Compute lesion score and total score
For each lesion: Lesion score = area × density factor. The total Agatston score is the sum of all lesion scores across major coronary arteries.
If slice thickness differs from 3 mm, many workflows apply a correction factor. This calculator applies: corrected score = raw score × (3 / slice thickness).
How to interpret your CAC score (general guide)
- 0: No detectable calcified plaque
- 1-10: Minimal plaque
- 11-100: Mild plaque burden
- 101-400: Moderate plaque burden
- >400: Extensive plaque burden
These categories are broad screening ranges. Clinical interpretation should include symptoms, family history, LDL-C, blood pressure, and preventive treatment goals.
When this calculator is useful
This tool is most helpful if you already have lesion-level CAC scan measurements and want a transparent way to estimate total Agatston score and vessel-level contribution.
- Quick educational review of how scoring works
- Approximate manual verification of report math
- Understanding whether score is concentrated in LAD, RCA, LCx, or left main
Important limitations
- Not all high-risk plaque is calcified; soft plaque is not captured by CAC alone.
- Image quality, reconstruction settings, and scanner protocol can affect measurements.
- Risk is not determined by CAC score alone; overall cardiovascular profile matters.
- This page is informational and cannot replace physician interpretation.
What to discuss with your clinician
If your score is 0
You may have lower short-term risk, but this does not guarantee zero risk. Continue lifestyle prevention and follow your clinician’s plan based on your full profile.
If your score is above 0
Ask about preventive strategy: LDL-lowering targets, blood pressure control, exercise programming, nutrition quality, sleep, glucose control, and smoking cessation if relevant.
Frequently asked questions
Is a higher Agatston score always dangerous?
A higher score usually means more calcified plaque burden, which correlates with increased risk. However, treatment decisions should be individualized and based on complete clinical context.
Can my score go down?
CAC is generally used as a marker of cumulative plaque calcification, and absolute score reduction is uncommon. Prevention focuses on reducing future events and slowing disease progression.
Should everyone get a CAC scan?
Not necessarily. It is commonly considered for selected adults where risk is uncertain and scan results could meaningfully change management.