kakdo° Angle Protractor

See Duo opening angles. Measure and save photo angles. kakdo° shows a compatible iPhone Duo's opening angle as its hinge moves, along with its supplementary angle. You can also measure angles in photos, keep several angles on one image, add notes, save measurements locally, and export PNG or CSV. One-time purchase, with no ads or subscriptions. Photo features require iOS/iPadOS 26.5 or later. Live hinge readings require compatible iPhone Duo hardware, iOS 27.1 or later, and available public-API data. Photo measurements are 2D image-plane angles and may differ from real-world angles.