Does a car compass actually work?

This is something I wanted to know, so I bought one.

Short answer:

Yes, it works, conditionally.

What are the conditions? That's the long answer.

Long answer:

Car compasses are cheap. They come in many shapes and sizes, and yes they are different from a trail compass (Cammenga is the best brand for trail and field use) because a car compass is a ball that sits in liquid while a trail compass is flat.

The only place in a car a ball compass can be mounted where it will actually work is in the center of the windshield. Why? That's the only mounting place furthest away from metal so the magnet in the compass can work.

If you were to mount a compass to the side, the magnet is going to attract to the window frame and it won't read properly. Mount it high or low on the glass and you get the same problem.

It also doesn't help there are several US states that say it's illegal to mount anything to the windshield at all.

I have seen one and only one compass that hangs down from the rear view mirror, which you can see here. Does that actually work? It should, but I don't know how accurate that would be since you get close to the center of the windshield but not exact center.

Is that hanging compass legal in all 50 states? No, because some states have laws written saying you can't have anything hanging off the rear view mirror. While I seriously doubt a cop would pull over somebody for that, yeah, your state may be one of those nothing-dangling-from-the-mirror places. You'll have to check your local laws for that one.

The other option is to use a compass on some kind of bean bag mount (one for a phone would probably work because of the grips) and then place it in the center of the dashboard. No, it won't reach the center of the windshield, but your compass should be mostly accurate.

Why bother with a car compass?

If your car navigation system decides to have an "off day" or just outright fails, at bare minimum you should at least know what cardinal direction you're driving. This is especially true if you're in unfamiliar territory.

The magnetic poles of the planet never have an off day. They always work.

Published 2023 Oct 3