ISO 838 is a standard for the dimensions and location of filing holes punched in paper is International Standard. Two holes with a diameter of 6±0.5 mm are punched into the paper. The centers of these holes are 80±0.5 mm apart and have a distance of 12±1 mm to the nearest edge of the paper. The holes are located symmetrically in relation to the axis of the sheet or document.
Any paper format that is at least 100 mm high (e.g., ISO A7 and larger) can be filed using this system. A printed document with a margin of 20–25 mm will accommodate ISO 838 filing holes.