Duke Treadmill Score Calculator

Understanding the Duke treadmill score calculator — concept and principle

The Duke treadmill score (DTS) turns the three most important findings of a standard exercise ECG test into one number that estimates the risk of serious coronary artery disease and death. It is used after a Bruce-protocol treadmill test in people with suspected coronary disease, to help decide whether they can be managed conservatively or need further testing such as imaging or angiography.

Minutes walked add points; ST change and chest pain take them away. The default example scores 4, one point short of low risk.

How it is calculated

DTS = exercise time − 5 × ST deviation − 4 × angina index

Exercise time: minutes completed on the standard Bruce protocol.
ST deviation: the largest ST-segment depression or elevation (in mm) during or after exercise, excluding lead aVR.
Angina index: 0 = no angina, 1 = angina that did not stop the test, 2 = angina that was the reason for stopping.

Risk groups: low for a score of +5 or more, moderate from −10 to +4, high for −11 or less.

The principle

Each term captures a different part of the heart's response to stress. Long exercise time reflects good functional capacity, which is one of the strongest predictors of survival. ST deviation reflects ischaemia seen on the ECG, and angina reflects ischaemia felt by the patient. The weights came from a survival model fitted to Duke University patients, so 1 mm of ST change "costs" as much as five minutes of exercise.

Worked example

Exercise time = 9 minutes.
ST deviation = 1 mm, so 5 × 1 = 5.
Angina index = 0, so 4 × 0 = 0.
DTS = 9 − 5 − 0 = 4.
A score of 4 falls in the −10 to +4 band, so the risk group is moderate, just one point below the low-risk cut-off.

Each point is the calculator re-run with only “Exercise time (minutes, Bruce)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Exercise time (minutes, Bruce)	Duke score
2.25	-2.75
4.5	-0.5
6.75	1.75
9	4
11.2	6.25
13.5	8.5
18	13

How to read the result

Where does your result fall?

In the original cohorts, mortality rose markedly from the low to the high group: low-risk patients generally have an excellent outlook and are often managed without invasive testing, whereas high-risk patients are commonly referred for coronary angiography.

Common mistakes

Using exercise time from a protocol other than Bruce.
Entering the ST change in a lead such as aVR, or counting resting ST changes that were already present.
Scoring angina as 2 when the test was stopped for fatigue or breathlessness rather than chest pain.

Keep in mind: The DTS was validated in people with suspected coronary disease and an interpretable resting ECG. It is less reliable with left bundle branch block, paced rhythm, digoxin, marked resting ST changes or pre-excitation. This is not a diagnosis; a cardiologist interprets the full test.

Frequently asked questions

Is a negative Duke treadmill score bad?

Not necessarily. Scores from −1 to −10 are still in the moderate band. Only −11 or lower is classed as high risk.

Why is exercise time so important?

Exercise capacity is a powerful predictor of survival on its own, independent of ECG changes.

Can I calculate it for a cycle ergometer test?

No. The formula is tied to Bruce treadmill minutes, so other protocols need conversion and are not directly comparable.

Sources: Mark DB et al. Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease. N Engl J Med 1991. · Mark DB et al. Exercise treadmill score for predicting prognosis in coronary artery disease. Ann Intern Med 1987.

Checked 8 Nov 2026. Mark et al., NEJM 1991.

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