Emergency Medicine Calculators
All Emergency Medicine calculators
- Canadian Syncope Risk Score CalculatorCalculate Canadian Syncope Risk Score.
- NEWS2 CalculatorNational Early Warning Score 2.
- PSI/PORT Pneumonia Severity CalculatorCalculate PSI/PORT Pneumonia Severity.
- San Francisco Syncope Rule CalculatorCalculate San Francisco Syncope Rule.
- Sgarbossa Criteria Calculator for MI in LBBBCalculate Sgarbossa Criteria Calculator for MI in LBBB.
- SMART-COP CalculatorPneumonia Severity Score.
- Wells Score Calculator for Suspected Deep Vein Thrombosis (DVT)Calculate Wells Score Calculator for Suspected Deep Vein Thrombosis (DVT).
- Wells Score Calculator for Suspected Pulmonary EmbolismCalculate Wells Score Calculator for Suspected Pulmonary Embolism.
Emergency medicine is decision making under uncertainty with the clock running. These eight tools answer the questions that dominate every shift: is this a clot, how sick is this patient, can they go home, and is that ECG hiding a heart attack. They do not replace the history and examination, but they turn gestalt into something measurable, defensible and teachable.
In short: Free emergency medicine calculators: Wells DVT and PE, NEWS2, PSI/PORT, SMART-COP, Sgarbossa criteria and syncope risk tools for ED decisions. Browse the calculators below, each with an interpretation guide.
What emergency medicine covers, and the clinical questions these tools answer
Emergency medicine cares for undifferentiated acute presentations, and its central skill is risk stratification: sorting the patients who can safely wait, or go home, from those who need immediate action. The two Wells scores tackle the most feared diagnostic miss in the department, venous thromboembolism, giving a pre-test probability for deep vein thrombosis and for pulmonary embolism that decides whether a D-dimer can rule out or imaging must rule in. The Sgarbossa criteria answer a narrower but equally high-stakes question: does this patient with left bundle branch block have an acute myocardial infarction, when the usual ST-segment rules no longer apply.
Disposition is the other half of the job. The PSI, also called PORT, and SMART-COP scores grade pneumonia severity to guide who needs admission, who needs the intensive care unit, and who can be treated at home. The Canadian Syncope Risk Score and the San Francisco Syncope Rule estimate short-term risk after a faint, separating the patients who need monitoring and workup from those who can be discharged with safety netting. Underneath all of this, NEWS2 watches for deterioration: a single number built from routine observations that triggers escalation before the patient arrests.
When clinicians and students use these calculators
The Wells scores are used at the bedside in real time, often while the D-dimer is being drawn, because the result decides the test pathway: low probability plus a negative D-dimer excludes, while moderate or high probability goes to imaging regardless. Sgarbossa is scored at the ECG machine, in the resuscitation room, where a left bundle branch block meets chest pain and the catheter laboratory needs an answer in minutes.
NEWS2 belongs to triage, the ward and the handover: it is calculated with every set of observations and its thresholds drive the escalation protocol. The pneumonia scores are scored once the diagnosis is made, usually in the emergency department or the acute medical unit, and they feed directly into the admission decision and the conversation with the patient. The syncope tools are used after the initial assessment is complete, when the question narrows to disposition. For students, these are the rules examiners love: know when each applies, what each changes, and where each fails.
How to interpret results, and what they change in practice
Both Wells scores use two-level or three-level models, and the crucial point is that they must be combined with D-dimer correctly: a low pre-test probability with a negative D-dimer safely excludes, but a high probability needs imaging even with a negative D-dimer. The most subjective item, whether an alternative diagnosis is less likely than the clot, is also the most powerful, which is why the score rewards clinical judgement rather than replacing it.
NEWS2 scores from 0 to 20, with higher scores triggering more urgent review; a score of 7 or more is the usual threshold for emergency assessment, while a score of 5 or 6 prompts urgent review. The pneumonia scores sort patients into classes: PSI classes I to III are generally managed as outpatients, classes IV and V are admitted, and SMART-COP identifies those likely to need intensive respiratory or vasopressor support. The modified Sgarbossa criteria award points for concordant ST elevation, excessively discordant ST deviation and concordant ST depression in V1 to V3, with a total of 3 or more supporting the diagnosis of occlusion. The syncope tools identify low-risk patients suitable for discharge, but none of them clears a patient whose story still worries you.
Limitations and pitfalls
Decision rules are only as good as their derivation populations. The Wells scores were built in patients already suspected of having a clot, so they do not apply to unselected patients and they perform poorly when the subjective items are scored carelessly. Sgarbossa has modest sensitivity: a negative result does not exclude infarction, and the criteria demand careful ECG measurement that is hard under pressure.
NEWS2 is not validated in pregnancy, in children, or in patients with chronically abnormal physiology unless the appropriate oxygen saturation scale is used, and a reassuring score never overrules a deteriorating patient. The syncope rules were derived to predict short-term serious outcomes, not to diagnose the cause of the faint, and syncope in older patients is frequently multifactorial. Every rule in this library shares one limitation: it was validated on groups, and the patient in front of you is an individual.
How to use this library
Score the Wells criteria before the D-dimer result arrives, so the test pathway is decided by probability rather than by the number you hope to see. Calculate NEWS2 with every observation set and act on the threshold, not on how the patient looks from the doorway. Use the pneumonia and syncope scores to structure the disposition conversation and document them in the notes, so the reasoning is visible to the next clinician. And treat Sgarbossa as one input to the reperfusion decision, alongside the story, the haemodynamics and a senior opinion.
Related specialities
Frequently asked questions
What is the Wells score for pulmonary embolism used for?
The Wells score for pulmonary embolism estimates the pre-test probability of PE from clinical features such as signs of DVT, tachycardia, immobilisation, previous VTE, haemoptysis, malignancy and whether PE is the most likely diagnosis. Combined with D-dimer, it decides whether imaging is needed: low probability with a negative D-dimer excludes PE, while higher probability requires CT pulmonary angiography.
When should I use NEWS2?
NEWS2 should be calculated with every set of adult observations in acute care, including triage, wards and handover. It aggregates respiratory rate, oxygen saturation, temperature, blood pressure, pulse and conscious level into a score from 0 to 20, with thresholds that trigger urgent or emergency review. Use the second oxygen saturation scale for patients at risk of hypercapnic respiratory failure.
What is the difference between PSI/PORT and SMART-COP?
Both stratify pneumonia, but they answer different questions. PSI, also called PORT, estimates thirty-day mortality across five classes and guides the admission decision. SMART-COP predicts the need for intensive respiratory or vasopressor support and is more useful for deciding the level of care once admission is planned.
Can the Sgarbossa criteria diagnose a heart attack in left bundle branch block?
They can support the diagnosis when the usual ST-segment criteria do not apply, because bundle branch block distorts repolarisation. A modified Sgarbossa score of 3 or more makes acute coronary occlusion likely and should prompt urgent cardiology involvement. However, sensitivity is modest, so a negative score does not exclude infarction when the story is convincing.
Do syncope decision rules replace clinical judgement?
No. The Canadian Syncope Risk Score and the San Francisco Syncope Rule estimate short-term risk of serious outcomes after an emergency department visit for syncope, and they help identify low-risk patients suitable for discharge. They do not diagnose the cause, they do not cover every high-risk feature, and a concerning history should always overrule a reassuring score.
Medical disclaimer
These calculators are educational tools for clinicians, students and informed readers. They do not provide medical advice, and no score or result should replace the judgement of a qualified health professional who has seen the patient. If you are unwell or worried about a result, seek professional care promptly.