Wells Score Calculator (DVT & PE)
Pre-test probability for deep vein thrombosis and pulmonary embolism: both Wells scores on one page, with the three-tier and two-tier interpretations.
The Wells scores turn a clinical impression into a documented pre-test probability — the number that decides whether a D-dimer can safely rule out clot or whether the patient goes straight to imaging. This page carries both scores: the nine-item Wells criteria for DVT (including the −2 for an alternative diagnosis) and the seven-item Wells score for PE, each reported in both the classic three-tier bands and the two-tier "likely / unlikely" split used with D-dimer pathways.
Wells score for DVT
Wells score for PE
How the bands are used
| Score | Three-tier interpretation | Two-tier interpretation |
|---|---|---|
| Wells DVT | ≤0 low · 1–2 moderate · ≥3 high | ≤1 DVT unlikely · ≥2 DVT likely |
| Wells PE | <2 low · 2–6 moderate · >6 high | ≤4 PE unlikely · >4 PE likely |
The two-tier split is the one wired into most modern pathways: "unlikely" plus a negative high-sensitivity D-dimer generally excludes the diagnosis without imaging, while "likely" bypasses D-dimer entirely and goes to imaging. The most subjective DVT item — "alternative diagnosis at least as likely," worth −2 — is also the most powerful: it can pull a patient with several physical findings back into the low band, which is exactly why the reasoning behind it should be documented. For billing and audit purposes, the documented score matters: it is the medical-necessity evidence behind the D-dimer, the ultrasound, or the CTPA, and its absence is a recurring finding in imaging denials reviewed by our medical coding support team.
Disclaimer: This calculator is educational only and is not medical advice. It does not replace clinical judgment or your local VTE protocol. A Wells score never overrides an unstable presentation — patients with shock, severe dyspnea, or syncope need emergency evaluation regardless of score.
Frequently asked questions
Which interpretation should I use — three-tier or two-tier?
Both are published and in use. The two-tier version (DVT ≤1 / PE ≤4 = "unlikely") pairs with D-dimer testing and is what most emergency and outpatient pathways use today. The three-tier version (low / moderate / high) is the original stratification and still appears in guidelines and older protocols. This page reports both so the documented score matches whichever pathway your service follows.
Why does the DVT score subtract 2 points for an alternative diagnosis?
The −2 item is what makes Wells a clinical score rather than a checklist of leg findings. If another diagnosis — a ruptured Baker's cyst, cellulitis, a muscle tear — explains the presentation at least as well as DVT, the pre-test probability drops sharply even when swelling or tenderness is present. Document which alternative diagnosis you had in mind.
Can a low Wells score rule out DVT or PE by itself?
No. A low or "unlikely" score is combined with a negative high-sensitivity D-dimer to exclude the diagnosis in the standard pathway. A low score with a positive D-dimer still needs imaging, and a "likely" score needs imaging regardless of D-dimer. The score stratifies; it does not rule out on its own.