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.