EP Calipers

EP Calipers allows you to use electronic calipers to make measurements on images of ECGs or EP recordings.  Use time calipers to measure intervals or heart rate, amplitude calipers to measure voltage, and angle calipers for specialized uses such as evaluating Brugada Syndrome. See this post for more details.

EP Calipers is available for iPhone or iPad,  Android devices,  Mac, and Microsoft Windows™.

Get EP Calipers

Get it on Google Play Get it from Microsoft

Notes on EP Calipers for Windows

There are two ways to get EP Calipers for Windows.  The first way is to download a zip file containing the program, available from FastSpring.  Unzip the downloaded file and double-click on setup.exe to install the program.

The second version is available from the Microsoft App Store.

Both versions are identical in function.  Which version you should download depends on whether you want to have a self-contained version of the program or want to use the Microsoft App Store.  Both versions will run on 32-bit and 64-bit versions of Windows 10.  Updates to the program are free for both versions; however users with the Microsoft App Store version will receive automatic update notices, which is not (at present) possible via FastSpring.  Purchasers of the FastSpring version of EP Calipers will be emailed a coupon for free updates shortly after their purchase.  Email me at mannd@epstudiossoftware.com if you don’t receive this coupon.  Follow me on Twitter (@manndmd) to hear about new version releases.

It is possible to run the FastSpring version on earlier versions of Windows (back to Vista SP2!); however,  it is necessary to download the Windows Universal CRT update.  Please read the instructions of the linked page carefully to set up your system.

The latest version of EP Calipers for Windows (2.0.0 and later versions) happily now has a transparent window feature that is working well regardless of how you install it, from FastSpring or the Microsoft App Store.


Add time, amplitude, or angle calipers
Time caliper before calibration
Measure a known interval to calibrate (e.g. 5 “boxes” at 25 mm/sec standard ECG speed which equals 1000 msec)
Caliper after calibration
Calipers maintain calibration with image zoom
Toggle between interval measurements and heart rate
Measure mean intervals and heart rates. Useful for irregular rhythms like atrial fibrillation.
Use calipers to measure the QT interval
Calculate the QTc using 4 different formulas
Using marching calipers to evaluate complex arrhythmias
Take photos of ECGs or load ECG images from your photo library. You can open PDF files with EP Calipers to analyze figures in published papers.

Other examples

Calculating QTc on a Windows PC
Transparent window on macOS Mojave
Measuring mean rate and interval on a Mac
Measuring mean rate and interval on a Mac
Making EP measurements on an iPad
Making EP measurements on an iPad
Marching calipers on the MacOS version
EP Calipers running on Microsoft Vista using the Universal CRT

YouTube videos

Note: some of these are a bit dated and lack some of the newer features, but they should give you a general idea of how to use the app on different platforms.

EP Calipers for Windows
(Note that this video does not demonstrate the transparent window mode)
EP Calipers on iPad
 Angle Calipers
New Features, including transparent window mode

Source code for iOS

Source code for Android

Source code for macOS

Source code for Windows

6 replies on “EP Calipers”

ep calipers is useless on Mac you can not get the measurements in ms and most of the features are grayed out. It would have been nice to know this before purchasing.

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