TIMI Risk Score Calculator (UA/NSTEMI)
Calculate the TIMI Risk Score for Unstable Angina/Non-ST Elevation MI (UA/NSTEMI). 7-factor risk stratification tool with 14-day event rates for death, MI, or urgent revascularization.
Risk Factor Assessment
Select Yes or No for each of the 7 TIMI risk factors
Is the patient 65 years of age or older?
At least 3 of 5: family history of premature CAD, hypertension, hypercholesterolemia, diabetes mellitus, current active smoker
Documented coronary artery disease with ≥ 50% stenosis on prior catheterization
Aspirin use is a risk factor because breakthrough ACS despite prophylaxis suggests more aggressive underlying disease
Two or more episodes of anginal chest pain in the preceding 24 hours (indicates unstable/accelerating pattern)
ST-segment deviation (depression OR transient elevation) ≥ 0.5 mm (0.05 mV) on presenting ECG. Not persistent ST elevation (STEMI).
Cardiac biomarkers (troponin I, troponin T, or CK-MB) above the 99th percentile. For hs-cTnI, typically > 14-26 ng/L depending on assay.
7 TIMI Risk Factors (1 point each)
TIMI Risk Score
Enter values to calculate
About This Calculator
The TIMI Risk Score for UA/NSTEMI is a validated clinical prediction tool that uses 7 binary risk factors to estimate the 14-day risk of death, myocardial infarction, or urgent revascularization in patients with unstable angina or non-ST-elevation myocardial infarction.
Development and Validation
The score was derived from the TIMI 11B trial (1,957 patients) and validated in the ESSENCE trial (1,953 patients) by Antman et al. in 2000. Each of the 7 predictors carried similar prognostic weight, making the score a simple arithmetic sum with no differential weighting.
When to Use the TIMI Score
The TIMI Score is designed for patients with suspected or confirmed UA/NSTEMI — NOT for undifferentiated chest pain in the emergency department. For initial ED evaluation of chest pain, the HEART Score is preferred. Use TIMI after a working diagnosis of UA/NSTEMI has been established to guide management intensity (conservative vs. invasive strategy).
TIMI UA/NSTEMI vs. TIMI STEMI
There are two different TIMI scores. This calculator is for UA/NSTEMI (7 binary factors, 0-7 points). A separate TIMI STEMI score exists (8 weighted factors, 0-14 points) for ST-elevation MI. These are NOT interchangeable.
2025 Guideline Status
Both TIMI and GRACE remain recommended in the 2025 ACC/AHA/ACEP ACS guidelines as validated prognostic tools for NSTE-ACS risk stratification.
Formula
TIMI Score = Sum of 7 binary risk factors (1 point each, range 0-7)Each criterion scores 1 point if present (maximum 7 points): • Age ≥ 65 years • ≥ 3 CAD risk factors (family history, hypertension, hypercholesterolemia, diabetes, smoking) • Known coronary artery disease (≥ 50% stenosis) • Aspirin use in prior 7 days • ≥ 2 anginal episodes in prior 24 hours • ST deviation ≥ 0.5 mm on presenting ECG • Elevated cardiac markers (troponin or CK-MB) Each predictor carries similar prognostic weight. The score is a simple arithmetic sum.
Clinical Considerations
- •TIMI Score is for Unstable Angina/NSTEMI only — do NOT use for STEMI (a separate TIMI STEMI score exists)
- •Not designed for undifferentiated chest pain — use HEART Score for initial ED evaluation
- •A TIMI score of 0 does NOT rule out ACS — it estimates lower risk, not absence of disease
- •Clinical judgment must always supplement risk scores
- •Original study used CK-MB; apply modern high-sensitivity troponin thresholds (99th percentile)
- •Aspirin use is a risk factor because breakthrough ACS despite prophylaxis suggests aggressive disease
Limitations
- •Binary variables lose clinical nuance (e.g., a 64-year-old scores the same as a 20-year-old)
- •Low specificity — many patients score in the intermediate range
- •Does not include hemodynamic data (blood pressure, heart rate, Killip class)
- •HEART Score outperforms TIMI for undifferentiated ED chest pain in most comparative studies
- •GRACE Score is more accurate for mortality prediction but requires more inputs
- •Predicts 14-day events only, not longer-term risk
- •Troponin thresholds not specified in original score (used CK-MB)
- •Validated in clinical trial populations which may not fully represent real-world ED patients
Interpretation Guide
| Range | Classification | Recommendation |
|---|---|---|
| <-2 | Low Risk | Low risk of death, MI, or urgent revascularization at 14 days. Consider observation unit or early discharge with close follow-up. Outpatient stress testing may be appropriate. |
| 2-4 | Intermediate Risk | Intermediate risk. Hospital admission recommended. Consider invasive strategy with cardiac catheterization during hospitalization per ACC/AHA guidelines. |
| 4-5 | High Risk | High risk. Early invasive strategy recommended per ACC/AHA guidelines. Cardiac catheterization with intent to revascularize during hospitalization. |
| 5-8 | Very High Risk | Very high risk. Early invasive strategy strongly recommended. Urgent cardiac catheterization with intent to revascularize. Consider GP IIb/IIIa inhibitors and dual antiplatelet therapy. |
Frequently Asked Questions
What is the TIMI Risk Score?
The TIMI Risk Score for UA/NSTEMI is a 7-factor clinical prediction tool that estimates the 14-day risk of death, myocardial infarction, or urgent revascularization in patients with unstable angina or non-ST-elevation MI. Each factor scores 1 point (range 0-7). It was developed from the TIMI 11B trial and validated in the ESSENCE trial by Antman et al. in 2000.
What are the 7 risk factors in the TIMI score?
The 7 TIMI risk factors are: (1) Age ≥ 65 years, (2) ≥ 3 CAD risk factors (family history, hypertension, hypercholesterolemia, diabetes, smoking), (3) Known CAD with ≥ 50% stenosis, (4) Aspirin use in prior 7 days, (5) ≥ 2 anginal episodes in prior 24 hours, (6) ST deviation ≥ 0.5 mm on ECG, (7) Elevated cardiac markers (troponin or CK-MB).
Why is aspirin use a risk factor in the TIMI score?
Aspirin use is a risk factor NOT because aspirin is harmful, but because patients already on aspirin who develop acute coronary syndrome have "breakthrough" events despite prophylaxis. This indicates more aggressive underlying coronary artery disease. It is a marker of disease severity, not a cause of risk.
What is the difference between TIMI and HEART scores?
The TIMI Score is for risk-stratifying patients with confirmed or suspected UA/NSTEMI (How severe is the ACS?). The HEART Score is for evaluating undifferentiated chest pain in the ED (Is this ACS?). Use HEART first for initial assessment, then TIMI after UA/NSTEMI is diagnosed. In head-to-head studies, HEART outperforms TIMI for ED chest pain evaluation.
What does a TIMI score of 3 mean?
A TIMI score of 3 falls in the intermediate risk category with a 14-day event rate of approximately 13.2% for death, MI, or urgent revascularization. This typically warrants hospital admission with consideration of an invasive strategy including cardiac catheterization.
Is there a different TIMI score for STEMI?
Yes. The TIMI score for STEMI is a completely separate tool with 8 weighted risk factors (score range 0-14) that predicts 30-day mortality after ST-elevation MI. It was developed by Morrow et al. in 2000. The two TIMI scores are NOT interchangeable — this calculator is for UA/NSTEMI only.
What are the 14-day event rates by TIMI score?
From the original TIMI 11B validation: Score 0-1: 4.7%, Score 2: 8.3%, Score 3: 13.2%, Score 4: 19.9%, Score 5: 26.2%, Score 6-7: 40.9%. Events include death, new or recurrent MI, or severe recurrent ischemia requiring urgent revascularization.
Is the TIMI score still recommended in current guidelines?
Yes. The 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for ACS continues to recommend both TIMI and GRACE as validated prognostic tools for NSTE-ACS risk stratification. TIMI is valued for its simplicity, while GRACE provides greater predictive accuracy for mortality.
What does elevated cardiac markers mean in the TIMI score?
Elevated cardiac markers means troponin I, troponin T, or CK-MB above the institutional upper limit of normal (99th percentile). With modern high-sensitivity troponin assays (hs-cTnI), this is typically > 14-26 ng/L depending on the specific assay used. The original study used CK-MB as the primary marker.
Can a TIMI score of 0 rule out ACS?
No. A TIMI score of 0 does NOT rule out acute coronary syndrome. It indicates lower risk (4.7% 14-day event rate for score 0-1), but ACS can still be present. The TIMI score is a prognostic tool for risk stratification, not a diagnostic tool for ruling out disease. Clinical judgment must always prevail.
References
1. Antman EM, Cohen M, Bernink PJ, et al.. The TIMI Risk Score for Unstable Angina/Non-ST Elevation MI: A Method for Prognostication and Therapeutic Decision Making. JAMA. 2000. doi: 10.1001/jama.284.7.835
View Source →2. Morrow DA, Antman EM, Charlesworth A, et al.. TIMI Risk Score for ST-Elevation Myocardial Infarction: A Convenient, Bedside, Clinical Score for Risk Assessment at Presentation. Circulation. 2000. doi: 10.1161/01.cir.102.17.2031
View Source →3. Writing Committee. 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes. Circulation. 2025
View Source →4. Writing Committee. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain. Circulation. 2021
View Source →Last updated: 2026-02-24
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