Abstract
An analytical, clear, accurate and explicit method to implement tilt correction, described in the ISO 12917:2017 standard for calibration of horizontal cylindrical tanks, is presented. The method is superior to the graphical method proposed in the standard up to 2017 and improves the one proposed in the current standard. Several of the difficulties presented by the correction method of the standard are discussed and clarified. As a novel contribution, two numerical tables were produced with tilt correction values, equivalent to Figure A-1 of ISO 12917:2002 and which have not been previously reported.