HAS-BLED Score Calculator — Bleeding Risk in Atrial Fibrillation

HAS-BLED is a simple additive point score published by Pisters and colleagues in Chest in 2010, derived from 3,978 patients with atrial fibrillation in the Euro Heart Survey. It estimates the risk of major bleeding within one yearfor a patient taking oral anticoagulation. “Major bleeding” in the derivation was defined as intracranial bleeding, a hospitalisation for bleeding, a haemoglobin drop of more than 2 g/dL, and/or bleeding needing a transfusion.

The mnemonic stands for Hypertension, Abnormal renal/liver function, Stroke, Bleeding, Labile INR, Elderly, and Drugs/alcohol. Although there are seven letters, the two “A” items (renal and liver) and the two “D” items (drugs and alcohol) each contribute a separate point, giving nine one-point criteria and a maximum score of 9. The calculation is:

1. Award 1 pointfor each of the nine criteria the patient meets. Each uses a specific threshold — for example, hypertension counts only when uncontrolled with systolic BP above 160 mmHg, and “elderly” means age over 65.
2. Sum the points. The total ranges from 0 to 9. There is no weighting or further arithmetic — HAS-BLED is a plain count.
3. Map the total to the 1-year major-bleeding rate from the Pisters 2010 cohort: 1.13% at score 0, rising through 1.02% (1), 1.88% (2), 3.74% (3), 8.70% (4) and 12.50% at score 5. Scores 6–9 had too few patients for a stable rate and are treated as at least as high as score 5.
4. Read the risk band. Under the 2020 ESC atrial fibrillation guidelines, a score of 3 or more is high bleeding risk; 0–2 is low-to-intermediate.
5. Act on modifiable factors. Four criteria are potentially reversible — uncontrolled hypertension, labile INR, concomitant antiplatelets/NSAIDs, and harmful alcohol use. The guideline recommends correcting these and reviewing more often, rather than withholding anticoagulation.

Because the score is a pure count, this tool cross-checks it two ways — summing the per-criterion breakdown and independently re-counting the raw inputs — and shows a “cross-checked” badge only when the two derivations agree.

• Pisters R, et al. A Novel User-Friendly Score (HAS-BLED)… Chest. 2010;138(5):1093–1100 — original derivation and rate table
• Hindricks G, et al. 2020 ESC Guidelines for the management of atrial fibrillation. Eur Heart J. 2021;42(5):373–498
• Practical-Haemostasis.com — HAS-BLED criteria and risk-table cross-check

The criteria, rate table, and high-risk threshold on this page were last cross-checked against the Pisters 2010 paper and the 2020 ESC guidelines on 2026-07-12. The page is reviewed whenever the ESC atrial fibrillation guideline is updated.