Wells score calculator for pulmonary embolism
Pre-test probability of pulmonary embolism, in both the three-tier and two-tier forms.
Scores 3.
Scores 3.
Scores 1.5.
Scores 1.5.
Scores 1.5.
Scores 1.
Scores 1.
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- Wells score (PE)
0.0
Low pre-test probability — around 6% prevalence.
- Two-tier interpretation
- PE unlikely
In the two-tier form, 4 or below is “unlikely”, the group in which a negative D-dimer is used to exclude PE.
- Criteria met
- None
This is a reference implementation of a published formula, provided for use by qualified healthcare professionals. It does not diagnose, does not account for the individual circumstances of any patient, and is not a recommendation for treatment. Confirm every result against your own institutional guidance before acting on it. Clinical judgement always takes precedence over a calculator.
About this calculation
The Wells score for PE estimates pre-test probability ahead of D-dimer and imaging. Both the original three-tier interpretation and the two-tier “likely or unlikely” form are shown, because guidelines differ on which to apply.
Formula
DVT signs 3 · PE most likely 3 · HR > 100 1.5 · immobilisation/surgery 1.5 · previous VTE 1.5 · haemoptysis 1 · malignancy 1
- Source
- Wells PS et al., Thrombosis and Haemostasis (2000)
- Methodology version
- 1.0.0
- Last reviewed
- 2026-10-28
What this does not account for
- “PE is the most likely diagnosis” carries three points and is a subjective judgement. It is the dominant source of variation between assessors.
- A pre-test tool. Applying it after a D-dimer result is known defeats its purpose.
- Not validated in pregnancy; use a pregnancy-specific pathway.
- An unlikely score with a negative D-dimer is what excludes PE. The score alone excludes nothing.