On-Screen EKG Measurement with Cardio Calipers

Q: How do I measure PR, QRS, and QT on a screenshot?

Open the EKG in any image viewer. Drag Cardio Calipers over the interval you want. Calibrate to 20 mm on the grid, then switch units to milliseconds.

Q: How do I calibrate Cardio Calipers to an EKG?

Stretch the calipers across 20 millimeters on the paper grid. Click Set, or choose Set Calibration to 20mm from the menu.

Q: How do I measure heart rate in BPM?

Cycle units to Heart Rate. Measure from P to P or R to R and the readout shows beats per minute.

Q: Can hospitals purchase with a purchase order?

Yes, for bulk orders. Download the free trial first so your team can verify the workflow. Contact us through the website for purchase orders, check payment, and volume licensing on Windows 10 and 11.

The Cardio Calipers is the fastest and most accurate way to measure electrocardiograms on a computer screen with pixel perfect accuracy.

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Full Specs

Measure PR, QRS, and QT on a screenshot

Open the EKG in any image viewer or PDF. Drag Cardio Calipers over the PR interval, QRS complex, or QT segment. Calibrate to 20 mm on the paper grid, then switch to milliseconds or beats per minute.

Works over any EKG image on your Windows desktop

Millimeters, milliseconds, millivolts, and BPM

Free trial download; purchase orders available for bulk orders

Our unique transparent Windows app floats above other software, allowing you to measure EKGs anywhere

Works with any software

The Cardio Calipers allow measurement of any EKG, no matter what format the EKG image is in.

Measure any EKG

Simply open up your EKG in any image viewer application and move the Cardio Calipers into place with the mouse.

Purchase with confidence

Download for free, and purchase the full featured version for just $49.50, we offer a risk free 30 day money back guarantee

Accurate and Simple to use

Manipulating the application is simply accomplished through use of the mouse, and a variety of keyboard controls allow for extra fine alignment. The Calipers can be aligned to measure an entire EKG complex, QT interval, PR interval, and QRS duration.

The Cardio Calipers can be used with any program as they float over other applications allowing quick and easy measurements. Read the full specs on how everything works.

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Unlock the full version

Unlock BPM readout, paper calibration, COM control, and custom skins. See the full specs after you purchase.

Full Rotation

360 degrees rotation has been included with the Calipers enabling them to be aligned to any EKG image.

Calibrated Units

The Cardio Calipers measure in millimeters, seconds, milliVolts and can also display the heart rate in beats per minute. The Calipers can be calibrated to individual EKG's at the touch of a button, and using the 'Paper Options' screen non-standard EKGs can be configured for measurement.

Cardio Calipers 4.0 now available, with semi transparent skins, and 360° rotation so you can measure any interval on an EKG.

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Discover the many uses of your Cardio Calipers

Keyboard Controls

The Cardio Calipers has numerous keyboard controls. By pressing Ctrl, Shift and Alt while dragging with the mouse the Calipers will extend, rotate or snap to 90 degrees.

Mouse feedback

To aid measurement the Caliper's mouse pointers will change making alignment intuitive and simple.

3rd Party Interfacing

The latest version of the Calipers provides the ability to be controlled from any external application through its COM interface.

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How to use Cardio Calipers

Short answers for the usual questions. The full manual, including keyboard shortcuts, is on getting started .

How do I measure PR, QRS, and QT on a screenshot?

How do I calibrate Cardio Calipers to an EKG?

How do I measure heart rate in BPM?

Can hospitals purchase with a purchase order?