The calculation is intended for the purposes of geometric and strength designs of spiral cylindrical torsion springs made of wires and rods in circular sections, cold formed, loaded with a static or cyclic loading. Application is developed in MS Excel, is multi-language and supports Imperial and Metric units and solves the following main tasks: - Automatic design of the spring. - Selection of the optimal design of the spring with respect to strength, geometry and weight. - Static and dynamic strength tests. - Support for Cold formed springs and Hot formed springs - Calculation of the working forces of a spring with known production and mounting dimensions. - Calculation of mounting dimensions for known spring loading and production parameters. - The application includes a table of commonly used spring materials according to ISO, ASTM/SAE, DIN, BS, JIS and others. - Support of 2D CAD (AutoCAD, AutoCAD LT, IntelliCAD, Ashlar Graphite, TurboCAD) and 3D CAD in full calculation package (Autodesk Inventor, SolidWorks, SolidEdge, Pro/E). The calculation is based on data, procedures and algorithms from specialized literature and the standards EN 13906-2, and DIN 2088.This module is a part of MITCalc - Mechanical and Technical Calculation Package for gear, belt and chain drives, springs, beam, shaft, bolt connection, shaft connection, tolerances and many others.