Medical Calculators

Emergency Medicine Clinical Calculators

Interactive scoring tools for clinical decision-making at the bedside. Select responses below and scores will calculate automatically. Each calculator can also be found on its relevant topic page.

Cardiac

HEART Score for Major Cardiac Events

Predicts 6-week risk of major adverse cardiac events (MACE) in patients presenting with chest pain.

Use in: Patients ≥21 years old with symptoms suggestive of ACS. Do not use if: New ST-elevation ≥1 mm, hypotension, life expectancy <1 year, or noncardiac illness requiring admission.

HEART Score

HEART Score Calculator

Criteria	Select One
History	Slightly suspicious (0)	Moderately suspicious (+1)	Highly suspicious (+2)
EKG	Normal (0)	Non-specific repolarization disturbance (+1)	Significant ST deviation (+2)
Age	<45 (0)	45–64 (+1)	≥65 (+2)
Risk Factors HTN, hypercholesterolemia, DM, obesity (BMI >30), smoking, family hx CVD, or hx atherosclerotic disease	No known risk factors (0)	1–2 risk factors (+1)	≥3 risk factors or hx atherosclerotic disease (+2)
Initial Troponin	≤normal limit (0)	1–3× normal limit (+1)	>3× normal limit (+2)
HEART Score	/ 10

Interpretation

0–3	Low Risk — 0.9–1.7% risk of MACE. Consider discharge with outpatient follow-up.
4–6	Moderate Risk — 12–16.6% risk of MACE. Consider admission for observation and further workup.
7–10	High Risk — 50–65% risk of MACE. Consider early invasive measures (cardiology consult, catheterization).

References

Six AJ, Backus BE, Kelder JC. Chest pain in the emergency room: value of the HEART score. Neth Heart J. 2008;16(6):191-196. PMID 18665203. Backus BE, Six AJ, Kelder JC, et al. Prospective validation of the HEART score for chest pain patients. Int J Cardiol. 2013;168(3):2153-2158. PMID 23465250. Mahler SA, Riley RF, Hiestand BC, et al. The HEART Pathway randomized trial. Circ Cardiovasc Qual Outcomes. 2015;8(2):195-203. PMID 25737484.

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CHA₂DS₂-VASc Score for Atrial Fibrillation Stroke Risk

Calculates stroke risk for patients with atrial fibrillation, to guide anticoagulation decisions.

Use in: Patients with nonvalvular atrial fibrillation.

CHA₂DS₂-VASc Score

CHA₂DS₂-VASc Score Calculator

Criteria	No (0)	Yes
Congestive heart failure (or LVEF ≤40%)	1	(+1)
Hypertension	1	(+1)
Age ≥75 years	1	(+2)
Diabetes mellitus	1	(+1)
Stroke/TIA/thromboembolism	1	(+2)
Vascular disease (prior MI, PAD, aortic plaque)	1	(+1)
Age 65–74 years	1	(+1)
Sex category (female)	1	(+1)
CHA₂DS₂-VASc Score	/ 9

Interpretation
0	Low Risk — 0.2% annual stroke risk (males). Anticoagulation generally not recommended.
1	Low-Moderate Risk — 0.6% annual stroke risk (males). Consider anticoagulation (esp. if not due to female sex alone).
≥2	Moderate-High Risk — ≥2.2% annual stroke risk. Oral anticoagulation recommended.

References

Lip GY, Nieuwlaat R, Pisters R, et al. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the Euro Heart Survey on Atrial Fibrillation. Chest. 2010;137(2):263-272. PMID 19762550. January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS Focused Update of the 2014 Guideline for Management of Patients With Atrial Fibrillation. J Am Coll Cardiol. 2019;74(1):104-132. PMID 30703431.

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Pulmonary

Wells' Criteria for Pulmonary Embolism

Objectifies risk of pulmonary embolism based on clinical criteria.

Use in: Patients with clinical suspicion for PE. Note: Use clinical judgment first; the Wells score helps quantify pre-test probability.

Wells Score for PE

Wells' PE Score Calculator

Criteria	No	Yes	Points
Clinical signs and symptoms of DVT (leg swelling, pain with palpation)	1		+3.0
PE is #1 diagnosis OR equally likely	1		+3.0
Heart rate >100 bpm	1		+1.5
Immobilization (≥3 days) OR surgery in previous 4 weeks	1		+1.5
Previous objectively diagnosed PE or DVT	1		+1.5
Hemoptysis	1		+1.0
Malignancy (treatment within 6 months or palliative)	1		+1.0
Wells' Score	points

Three-Tier Model

0–1	Low Risk — 1.3% incidence of PE. Consider D-dimer to rule out. Consider PERC rule.
2–6	Moderate Risk — 16.2% incidence of PE. Consider high-sensitivity D-dimer or CTA.
>6	High Risk — 37.5% incidence of PE. Consider CTA. D-dimer not recommended.

Two-Tier Model (Preferred by guidelines)

0–4	PE Unlikely — 12.1% incidence. Consider high-sensitivity D-dimer; if negative, stop workup.
>4	PE Likely — 37.1% incidence. Consider CTA testing.

References

Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thromb Haemost. 2000;83(3):416-420. PMID 10744147. van Belle A, Büller HR, Huisman MV, et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295(2):172-179. PMID 16403929.

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PERC Rule for Pulmonary Embolism

Rules out PE if NO criteria are present and pre-test probability is ≤15% (low risk by gestalt).

Use in: Low-risk patients where PE has been considered but is not the leading diagnosis. Key point: ALL criteria must be negative (No) to rule out PE.

PERC Rule

PERC Rule Calculator

Criteria	No (0)	Yes (+1)
Age ≥50 years	1
Heart rate ≥100 bpm	1
SpO₂ <95% on room air	1
Unilateral leg swelling	1
Hemoptysis	1
Recent surgery or trauma (within 4 weeks requiring hospitalization)	1
Prior PE or DVT	1
Hormone use (oral contraceptives, HRT, or estrogenic hormones)	1
Positive Criteria	/ 8

Interpretation

Score = 0	PERC Negative — If pre-test probability is ≤15%, PE is effectively ruled out. No further workup needed (sensitivity 97.4%, NPV 99.5%).
Score ≥ 1	PERC Positive — Cannot rule out PE by PERC alone. Consider D-dimer, Wells' score, or CTA based on clinical suspicion.

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CURB-65 Score for Pneumonia Severity

Estimates 30-day mortality of community-acquired pneumonia (CAP) to help determine inpatient vs. outpatient treatment.

Use in: Adult patients with confirmed or suspected community-acquired pneumonia.

CURB-65 Score

CURB-65 Calculator

Criteria	No (0)	Yes (+1)
Confusion (new disorientation in person, place, or time)	1
Uremia — BUN >19 mg/dL (>7 mmol/L)	1
Respiratory rate ≥30 breaths/min	1
Blood pressure — SBP <90 mmHg or DBP ≤60 mmHg	1
Age ≥65 years	1
CURB-65 Score	/ 5

Interpretation & Disposition

0–1	Low Risk — 1.5% 30-day mortality. Consider outpatient treatment with oral antibiotics.
2	Moderate Risk — 9.2% 30-day mortality. Consider short inpatient stay or closely monitored observation.
3–5	High Risk — 22% 30-day mortality. Inpatient admission recommended. ICU if score 4–5.

References
Lim WS et al. Defining community acquired pneumonia severity. Thorax. 2003;58(5):377-382. PMID 12728155. Mandell LA et al. IDSA/ATS consensus guidelines on CAP. Clin Infect Dis. 2007;44:S27-72. PMID 17278083.

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Vascular

Wells' Criteria for DVT

Calculates risk of DVT based on clinical criteria.

Use in: Patients with clinical suspicion for deep venous thrombosis.

Wells Score for DVT

Wells' Criteria for DVT

Criteria	No	Yes	Points
Active cancer (treatment within 6 months or palliative)	1		+1
Bedridden recently >3 days or major surgery within 12 weeks	1		+1
Calf swelling >3 cm compared to other leg (measured 10 cm below tibial tuberosity)	1		+1
Collateral superficial veins (non-varicose)	1		+1
Entire leg swollen	1		+1
Localized tenderness along deep venous system	1		+1
Pitting edema confined to symptomatic leg	1		+1
Paralysis, paresis, or recent cast immobilization of lower extremities	1		+1
Previously documented DVT	1		+1
Alternative diagnosis at least as likely as DVT	1		−2
Wells' Score	points

Interpretation (Traditional)
≤0	Low Risk — 5% prevalence of DVT. Consider D-dimer to rule out.
1–2	Moderate Risk — 17% prevalence of DVT. Consider D-dimer or ultrasound.
≥3	High Risk — 53% prevalence of DVT. Ultrasound recommended.
Interpretation (Dichotomized)
≤1	DVT Unlikely — D-dimer to rule out.
≥2	DVT Likely — Ultrasound recommended.

References
Wells PS et al. Value of assessment of pretest probability of DVT. Lancet. 1997;350:1795-1798. PMID 9428249. Wells PS et al. Evaluation of D-dimer in suspected DVT. N Engl J Med. 2003;349:1227-1235. PMID 14507948.

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Neurological

Glasgow Coma Scale (GCS)

Assesses level of consciousness based on Eye, Verbal, and Motor responses. Score range: 3–15.

Use in: Any patient requiring neurological assessment — trauma, stroke, altered mental status. Note: GCS should not be used alone for clinical management decisions.

Glasgow Coma Scale (GCS)

Glasgow Coma Scale Calculator

Component	Response	Points
Eye Opening (E)	Spontaneous	+4
	To verbal command	+3
	To pain	+2
	No eye opening	+1
Verbal Response (V)	Oriented	+5
	Confused	+4
	Inappropriate words	+3
	Incomprehensible sounds	+2
	No verbal response	+1
Motor Response (M)	Obeys commands	+6
	Localizes pain	+5
	Withdrawal from pain	+4
	Flexion to pain (decorticate)	+3
	Extension to pain (decerebrate)	+2
	No motor response	+1
GCS Score	/ 15

Interpretation

13–15	Mild brain injury
9–12	Moderate brain injury
3–8	Severe brain injury — consider intubation if unable to protect airway

References
Teasdale G, Jennett B. Assessment of coma and impaired consciousness. Lancet. 1974;2:81-84. PMID 4136544. Teasdale G et al. The Glasgow Coma Scale at 40 years. Lancet Neurol. 2014;13:844-854. PMID 25030516.

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Infectious Disease / Sepsis

qSOFA (Quick SOFA) Score for Sepsis

Identifies high-risk patients for in-hospital mortality with suspected infection outside the ICU.

Use in: Patients with suspected sepsis outside the ICU. Note: Per Sepsis-3 definitions, qSOFA ≥2 with suspected infection warrants further evaluation for organ dysfunction.

qSOFA Score

qSOFA (Quick SOFA) Score

Criteria	No (0)	Yes (+1)
Altered mental status (GCS <15)	0	1
Respiratory rate ≥22 breaths/min	0	1
Systolic BP ≤100 mmHg	0	1
qSOFA Score	0   / 3

Interpretation
0–1	Low Risk — Not high risk for in-hospital mortality. Continue standard evaluation.
≥2	High Risk — Associated with ≥10% in-hospital mortality. Consider ICU-level care, lactate, blood cultures, and broad-spectrum antibiotics.

References
Singer M et al. Sepsis-3 Definitions. JAMA. 2016;315(8):801-810. PMID 26903338. Seymour CW et al. Assessment of clinical criteria for sepsis. JAMA. 2016;315(8):762-774. PMID 26903335.

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SIRS Criteria

Defines the systemic inflammatory response syndrome.

Use in: Screening for SIRS in the setting of suspected infection. Note: SIRS + suspected infection = sepsis (per Sepsis-1/2 definitions). Sepsis-3 uses SOFA/qSOFA instead.

SIRS Criteria

SIRS Criteria

Criteria	No (0)	Yes (+1)
Temperature >38°C (100.4°F) or <36°C (96.8°F)	1
Heart rate >90 bpm	1
Respiratory rate >20 breaths/min or PaCO₂ <32 mmHg	1
WBC >12,000/mm³ or <4,000/mm³ or >10% bands	1
SIRS Criteria Met	/ 4

Interpretation
0–1	SIRS criteria NOT met — Fewer than 2 criteria present.
≥2	SIRS criteria MET — If infection is suspected or confirmed, meets criteria for sepsis (per Sepsis-1/2 definition). Note: Sepsis-3 uses qSOFA/SOFA criteria instead.

References
Bone RC et al. Definitions for sepsis and organ failure. Chest. 1992;101:1644-1655. PMID 1303622. Kaukonen KM et al. SIRS criteria in defining severe sepsis. N Engl J Med. 2015;372:1629-1638. PMID 25776936.

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ENT / Pharyngitis

Modified Centor (McIsaac) Score for Strep Pharyngitis

Estimates probability that pharyngitis is streptococcal and suggests management course.

Use in: Patients presenting with sore throat to guide testing and treatment.

Centor/McIsaac Score

Modified Centor (McIsaac) Score

Criteria	No (0)	Yes (+1)
Tonsillar exudates or swelling	0	1
Tender/swollen anterior cervical lymph nodes	0	1
Temperature >38°C (100.4°F)	0	1
Absence of cough	0	1
Age modifier (McIsaac modification)
Age 3–14 years	0	1 (+1)
Age 15–44 years	(0 points — default)
Age ≥45 years	0	-1 (−1)
Modified Centor Score	0   / 5

Interpretation & Management
≤0	~1–2.5% strep probability — No testing or antibiotics needed.
1	~5–10% strep probability — No testing or antibiotics needed (optional rapid strep if high clinical suspicion).
2–3	~11–35% strep probability — Rapid strep testing recommended; treat if positive.
4–5	~51–53% strep probability — Consider empiric antibiotics or rapid strep test.

References
Centor RM et al. The diagnosis of strep throat in adults. Med Decis Making. 1981;1:239-246. PMID 6763125. McIsaac WJ et al. A clinical score to reduce unnecessary antibiotic use. CMAJ. 1998;158:75-83. PMID 9475915.

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Orthopedic / Trauma

Ottawa Ankle Rule

Rules out clinically significant foot and ankle fractures to reduce use of x-ray imaging.

Use in: Patients presenting with ankle or midfoot pain after injury. Note: Sensitivity 96.4–99.6% for clinically significant fractures. Apply only in adults >18 years.

Ottawa Ankle Rules

Ottawa Ankle Rule

Criteria	No (0)	Yes (+1)
Ankle X-ray is required if there is pain in the malleolar zone AND any of the following:
Bone tenderness along distal 6 cm of posterior edge of tibia or tip of medial malleolus	1
Bone tenderness along distal 6 cm of posterior edge of fibula or tip of lateral malleolus	1
Inability to bear weight both immediately and in the ED (4 steps)	1
Foot X-ray is required if there is pain in the midfoot zone AND any of the following:
Bone tenderness at the base of the 5th metatarsal	1
Bone tenderness at the navicular	1
Inability to bear weight both immediately and in the ED (4 steps)	1
Positive Criteria	/ 6

Interpretation
Score = 0	No X-ray needed — Sensitivity 96.4–99.6% for clinically significant fractures.
Score ≥ 1	X-ray recommended — Ankle and/or foot x-ray indicated based on positive criteria location.

References
Stiell IG et al. A study to develop clinical decision rules for radiography in acute ankle injuries. Ann Emerg Med. 1992;21:384-390. PMID 1554175. Stiell IG et al. Decision rules for radiography in acute ankle injuries: refinement and prospective validation. JAMA. 1993;269:1127-1132. PMID 8433468.

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Disclaimer: These calculators are provided as clinical decision support tools only. They do not replace clinical judgment. Always consider the full clinical picture when making treatment decisions. Scoring systems referenced from peer-reviewed literature. See individual topic pages for complete references.