Rulers are great for measuring straight lines. But what if you need to measure the length of something less linear, like a curve, a wave, or a swerving mess of a line? That’s what the Curve Runner was built for.
A ruler that can measure the length of any line, you can use it with straight, curved, and even the most irregular lines you can think of. It’s a super-straightforward solution, too, saving you from the hassle of making up workarounds on the go, whether you’re doing measurements for a technical drawing, woodworking, or scale models of your favorite objects.
The Curve Runner is a round, rolling ruler with measurement markers along the edges, attached to a handle using a medical rivet and a steel washer. To use, simply place the starting point of the ruler at the beginning of a line, then start rolling it along the line’s length, following every turn while keeping count of how many times it makes a full revolution, in order to ensure you can get an accurate measurement. It comes in two variants: one with an 8-inch round ruler and another with a 20-cm round ruler, so there’s a suitable option, whether you work with English or Metric systems of measurement.  Both the handle and the ruler are made from clear acrylic, so your view will not be obscured at any point during use.
Want one? A Kickstarter campaign is currently running to fund the Curve Runner. Pledges to reserve a unit starts at $20.