Wells Score DVT Calculator
Free Wells score calculator for DVT. Tick the clinical criteria for an instant pre-test probability of deep vein thrombosis (low, moderate, or high).
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Tick every clinical feature that is present.
Show the interpretation
Educational decision aid for adults. The Wells score guides — but does not replace — clinical judgment and testing (D-dimer, ultrasound). Not medical advice.
How the Wells Score DVT Calculator Works
The Wells score for DVT is a validated clinical prediction rule that estimates how likely a patient is to have a deep vein thrombosis (DVT) before any imaging is done. Tick each clinical feature that is present, and the calculator returns the total score along with both the three-tier (low/moderate/high) and the simplified two-tier (unlikely/likely) interpretation.
The Formula
Wells DVT score = (sum of the nine +1 clinical criteria) − 2 (if an alternative diagnosis is at least as likely)
| Clinical criterion | Points |
|---|---|
| Active cancer (treatment/palliation within 6 months) | +1 |
| Paralysis, paresis, or recent leg immobilization | +1 |
| Recently bedridden >3 days or major surgery within 12 weeks | +1 |
| Localized tenderness along the deep venous system | +1 |
| Entire leg swollen | +1 |
| Calf swelling >3 cm vs. the other leg | +1 |
| Pitting edema confined to the symptomatic leg | +1 |
| Collateral (non-varicose) superficial veins | +1 |
| Previously documented DVT | +1 |
| Alternative diagnosis at least as likely as DVT | −2 |
Worked Example
A patient with active cancer (+1), whole-leg swelling (+1), calf swelling >3 cm (+1), and localized tenderness (+1), with no equally likely alternative diagnosis:
- Wells score = 1 + 1 + 1 + 1 = 4
- Three-tier: 4 ≥ 3 → high probability
- Two-tier: 4 ≥ 2 → DVT likely
A high-probability result means the next step is a compression ultrasound of the leg.
Interpreting the Score
- Three-tier: ≤0 low, 1–2 moderate, ≥3 high pre-test probability.
- Two-tier (modified): under 2 means DVT unlikely; 2 or more means DVT likely.
The score is the first step of a diagnostic pathway. When DVT is unlikely, a normal D-dimer can safely rule it out without imaging. When DVT is likely — or the D-dimer is raised — a leg ultrasound is used to confirm or exclude the clot.
Important Limitations
The Wells score is a probability estimate, not a diagnosis. It was validated in adult outpatients and should not be applied to pregnancy, suspected recurrent DVT in the same leg, or critically ill inpatients without caution. Always combine it with D-dimer, imaging, and the judgment of a qualified clinician. This calculator is for education only and does not provide medical advice.
Frequently asked questions
What is the Wells score for DVT?+
The Wells score for DVT is a clinical prediction rule that estimates the pre-test probability that a patient has a deep vein thrombosis. Nine clinical features each add 1 point, and 2 points are subtracted if an alternative diagnosis is at least as likely, giving a score that sorts patients into risk groups.
How is the Wells DVT score calculated?+
Add 1 point for each of: active cancer, leg paralysis or immobilization, recent bed rest or major surgery, localized deep-vein tenderness, whole-leg swelling, calf swelling over 3 cm, pitting edema, collateral superficial veins, and previously documented DVT. Subtract 2 points if another diagnosis is at least as likely. The total is the Wells score.
What do the Wells DVT score categories mean?+
In the three-tier scheme, a score of 0 or below is low probability, 1 to 2 is moderate, and 3 or more is high. In the simplified two-tier scheme, a score below 2 means DVT is unlikely and 2 or more means DVT is likely. The category determines whether D-dimer testing or ultrasound comes next.
What happens after the Wells score?+
A common pathway is: if DVT is unlikely (low risk), order a D-dimer; a negative D-dimer effectively rules out DVT without imaging. If DVT is likely (high risk) or the D-dimer is positive, order a compression ultrasound of the leg to confirm or exclude the clot.
Is the Wells score a diagnosis?+
No. The Wells score only estimates the probability of DVT before testing. It does not confirm or exclude a clot on its own and must be combined with D-dimer, ultrasound, and clinical judgment by a qualified clinician. This calculator is an educational aid, not medical advice.