Wells Score for DVT Calculator

The Wells score for deep-vein thrombosis is a clinical prediction rule derived by Wells and colleagues in 1997 and refined in 2003. It turns ten bedside findings into a single number that estimates how likely a leg DVT is before any imaging, a pretest probability. The tool above adds the point value of every criterion you tick and applies the published cut-offs. Nothing is uploaded; the calculation runs entirely in your browser.

Nine criteria each add one point when present, and one criterion subtracts two:

• Active cancer (treated within 6 months), +1
• Paralysis, paresis, or recent plaster cast, +1
• Bedridden ≥ 3 days or major surgery < 12 weeks, +1
• Localised deep-vein tenderness, +1
• Entire leg swollen, +1
• Calf ≥ 3 cm larger than the other side, +1
• Pitting oedema (symptomatic leg only), +1
• Collateral (non-varicose) superficial veins, +1
• Previously documented DVT, +1
• Alternative diagnosis at least as likely, −2

The total therefore ranges from −2 to +9. Two interpretation models then read that total:

Two-level / dichotomised (Wells et al., 2003; NICE NG158). A score of 2 or more is DVT likely; 1 or less is DVT unlikely. This is the model most modern guidelines use to drive testing, unlikely patients get a D-dimer (a negative result excludes DVT without a scan; a positive one leads to ultrasound), while likely patients go straight to a proximal-leg compression ultrasound.

Three-level (Wells et al., 1997). The same total is reported as low (≤ 0, ~5% DVT prevalence), moderate (1–2, ~17%) or high (≥ 3, ~53%). These prevalences are the DVT rates observed in the original derivation cohort, quoted as published. Because the boundaries differ, a total of exactly 2 is moderate on the three-level model yet already likely on the two-level model, the tool shows both so the disagreement is explicit rather than hidden.

To keep the arithmetic trustworthy, the underlying module computes the total two independent ways, once by summing the criteria table and once from the literal point formula, and only shows the “cross-checked” badge when the two agree to the point. Every cut-off and prevalence is a fixed value from the cited literature; there is no rounding, interpolation, or opinion in the scoring.

• Wells PS, et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. Lancet. 1997;350(9094):1795–1798
• Wells PS, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. 2003;349:1227–1235
• NICE guideline NG158: Venous thromboembolic diseases: diagnosis, management and thrombophilia testing (2020, updated 2023)
• MDCalc: Wells' Criteria for DVT (reference implementation)

The ten criteria, point values, both sets of cut-offs and the three prevalence figures on this page were last cross-checked against the sources above on 2026-07-13. This is an educational reference, not a medical device, and it stores no patient data.