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What is a Digital Protractor?

Jessica Reed
Jessica Reed

A digital protractor allows the user to measure angles with much more accuracy than a hand-held protractor. The digital protractor is electronic and comes with a variety of useful features. The angle measurements being taken are displayed on the screen for the user to read and record.

Many digital protractors consist of a movable arm and a small box in the center that holds the buttons and the display screen. The user places one edge along a straight line and adjusts the movable arm to line up with the next line. This creates the angle the user wants to measure. The results are displayed on screen. For example, if one arm of the protractor was straight and the other pointed straight up, the screen would read 90 degrees.

Manual protractors.
Manual protractors.

A normal, hand-held protractor requires the user to line up the straight edge with one line of the angle and wherever the second line forming the angle intersects the protractor, that number is the measurement of the angle. The problem with this method is a higher chance of misreading the angle. Even with the correct measurements, there is no way to measure angles that must be precise and cannot be off by even a fraction of a degree.

Hand-held protractors can be used to measure angles, but are considered less accurate than a digital protractor.
Hand-held protractors can be used to measure angles, but are considered less accurate than a digital protractor.

The digital protractor can measure angles exactly, making it much more reliable. This is especially helpful for carpenters or builders who are making cuts that must all line up and fit together. Those performing mathematics calculations will find the protractor extremely helpful in achieving correct results.

Other features improve the advantages of the digital protractor. Along with a display screen that shows the angle being measured, the protractor often has a "Hold" button which allows the user to save the current angle while measuring or examining a different area. Other buttons may allow the user to adjust the protractor and temporarily set that angle to zero.

For those who need to transfer angles to use later on, many digital protractors have a slot so they can be plugged into a computer. The data is then transferred from the digital protractor onto the computer for use. They also have other real world applications to them. Certain digital protractors can measure and advise the user what miter and bevel angles they need to cut when working on a project involving a miter saw. The measurements can then be stored on a computer and used in the future when the same cut needs to be repeated.

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Discussion Comments


@Charred - I can tell you this; the prior owner of the house that I live in could have used some digital tools to help him along.

Here and there I see sprawled about his attempts at some home improvement projects. He put a crown molding in the dining area, but his angles were way off.

There’s one whole corner piece that’s missing because he clearly got his measurements wrong. He could have gone to a home improvement store, bought a digital protractor angle finder, and his angle would be spot on.

Now I’ll have to fix it. I agree, however, that while these units may be a bit pricey they are simply indispensable for home improvement projects.


@Mammmood - If you’re doing a house project it would definitely be worthwhile, I agree.

In that case you may want to get a digital level protractor as well. These are standard tools in the carpenter’s toolkit. There’s no way I could keep a level line of sight without one.

What I like best about the digital protractor is that you can plug it into your computer. This would be handy if you were remodeling a kitchen or even building a house, and using software to draw up your plans.

You can feed your angle measurements directly into the software to make sure that everything lines up correctly.


I had to use a protractor to help my daughter with her physics problems.

I agree with everything that the article says about the limited reliability of the standard protractors. You would think that with the importance of absolute precision needed in some of your formulas and stuff, they wouldn’t ask you to use a regular protractor.

However, I think I know why those trusty pieces of plastic are still used – price. I looked up prices for a digital electronic protractor online and they are in the hundreds of dollars.

I am certainly not going to spend that kind of money for a protractor, not after having shelled out money for a high quality scientific calculator.

Perhaps if I find a personal need for a digital protractor – a house project for example that requires accurate angle measurements to be successful – I will go out and buy one.

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    • Manual protractors.
      By: creative soul
      Manual protractors.
    • Hand-held protractors can be used to measure angles, but are considered less accurate than a digital protractor.
      By: Tatesh
      Hand-held protractors can be used to measure angles, but are considered less accurate than a digital protractor.