In various example embodiments, devices, systems, and methods for a waist measuring belt are provided. An example waist measuring belt is made up of a belt buckle frame with attachments for a belt strap. The belt further includes a position measuring module coupled to the belt buckle frame that measures an attachment position of a second end of the belt strap to the belt buckle frame. The belt also includes a tension measuring module coupled to the belt buckle frame that measures a tension through the belt buckle frame and the belt strap. A memory and a wireless communication module attached to the belt may be used to store measurements and communicate with a mobile device or server. In various embodiments, estimated user waist sizes over time using measured values and belt-specific data may be used to estimate a user's waist size and generate a waist size history.