Measurements are hard to do on your own. But! I’ve found a few resources to help.
ZoZo Fit: 3D Body Measurements made easy. This is the first one I tried. I spent the $199 for the suit. They now also have an app only subscription, no suit required. By my experience, this works better without the suit. iOS and Android.
MeThreeSixty: Visualize your weight-loss journey with 3D body scanning from your smartphone. There is no fee to use MeThreeSixty. iOS and Android.
BodyGram: “Easiest and most reliable way to obtain body measurements”. BodyGram also incorporates some posture metrics. There is no fee. I’m using the iOS version, I don’t know if there is an Android.
Spren: Convenient, Accurate Health Assessment and Body Composition Analysis. iOS only. In addition to the Body Scan, I am also using the Blood Labs and Vitals service. Spren provides body composition analysis, but, not measurements.