By Zencalcy Editorial TeamLast reviewed About us
CHADS2 is a five-item score that estimates stroke risk in people with atrial fibrillation. Each item adds one point except prior stroke or transient ischaemic attack, which adds two. This calculator sums the selected factors and reports the total with its usual low, moderate or high band.
Stroke-risk score for atrial fibrillation.
CHADS2 = CHF(1) + hypertension(1) + age ≥75(1) + diabetes(1) + stroke/TIA(2)
The maximum is 6 because stroke or TIA carries two points. A score of 0 is usually treated as low risk, 1–2 as moderate and 3 or more as high. The score is a conversation aid, not a prescription: kidney function, bleeding risk, falls and patient preference all affect anticoagulation decisions.
| Symbol | Meaning |
|---|---|
| Score | Total CHADS2 points, from 0 to 6. |
| Stroke/TIA | Prior stroke or transient ischaemic attack adds two points. |
| Age | Age 75 or older adds one point. |
Congestive heart failure adds 1, hypertension adds 1, age 75 or older adds 1, diabetes adds 1 and prior stroke adds 2, for a total of 6 out of 6. A 60-year-old with hypertension only scores 1 out of 6, which sits in the moderate band despite being otherwise well.
CHADS2 compresses several risk factors into a small integer, which makes it easy to remember at the bedside but also easy to over-interpret. The score separates people into broad groups, and the boundaries between those groups are not sharp. A person with a score of 2 may have very different risk from another person with the same total if their blood pressure, kidney function or age differ. The score also says nothing about bleeding risk, which must be weighed alongside stroke risk when anticoagulation is considered. Use the total to structure a conversation, not to end one. If you are taking an anticoagulant, never stop or change it because of a calculator result; speak to the clinician who manages your treatment.
Continue with the Mean Arterial Pressure Calculator, Pulse Pressure Calculator, or the QTc Calculator — or browse more cardiology tools and all health calculators.
It estimates the risk of stroke in people with atrial fibrillation. Higher totals are associated with more strokes per year, but the score is a broad stratification tool rather than a precise individual probability.
Blood pressure, ECG and risk scores are screening aids, not diagnoses. A single reading can be misleading; trends and proper technique matter. Scores estimate population risk and do not replace clinical assessment, anticoagulation decisions or emergency care.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026