The best alternatives to M-30+ are Audio Ruler, Instant Measure, and VH-80. If these 3 options don't work for you, we've listed a few more alternatives below.
Unusually to other apps, the measurement process is based on the sound. Specifically, the distance traveled by a sound way from point A (phone speaker) to point B (earphones). The algorithm behind the app is fueled by advanced math! It's pure science!
Using the advanced sensors on the latest iPhones, Instant Measure lets you instantly measure the distance between your camera and an object. Just use the front camera and align the marker on the center of the screen to instantly get a measurement readout.
Our tool is the fastest and most efficient way to measure anything on your screen. PixelsMeasure works on the whole screen, across all apps, and you can measure anything on your macOS, iOS and iPadOS.