Geometric design and strength check of internal spur gear with straight and helical toothing. Application is developed in MS Excel, is multi-language and supports Imperial and Metric units and solves the following main tasks: - Calculation of helical and straight toothing (internal). - Automatic design of a transmission with the minimum number of input requirements. - Design for entered coefficients of safety (static, dynamic). - Calculation of complete geometric parameters (including corrected toothing). - Optimization of toothing by use of proper correction (balancing specific slips, miminizing specific slips, strength...). - Calculation of strength parameters, safety check. - Design of gearing for exact axis distance. - Supplementary calculations (calculation of parameters of the existing gear, temperature rise, design of shafts, check dimensions). - Support of 2D and 3D CAD systems. - Drawings of an accurate tooth shape including data (X,Y coordinates). - 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 calculations use procedures, algorithms and data from standards ANSI, ISO, DIN, BS and specialized literature. Used standards: ISO 6336, ISO 1328, DIN 3990, ANSI B6.1-1968, AGMA 2001-C95, AGMA 2001-D04, AGMA 908-B89/95 and others.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 You can free download MITCalc - Internal Spur Gear Calculation 1.11 now.