A web winding and measuring system is provided. The system includes a rotatably-mounted spool onto which a web of material is wound to form a roll. The system additionally includes a light-emitting device configured to illuminate the roll by light, providing a line on a cylindrical surface of the roll in a cross-machine direction, a light-receiving device configured to detect the line and generate measurement data from the detected line, and a computing device communicatively coupled to the light-receiving device and configured to receive the measurement data and calculate a diameter of the roll.