ODOP:Spring is described as 'More than a spring calculator, ODOP:Spring is free and open-source spring design software for engineering custom helical coil springs, including compression, torsion and extension springs' and is a Calculator in the education & reference category. There are five alternatives to ODOP:Spring for a variety of platforms, including Windows Mobile, Android, iPhone, Mac and Windows apps. The best ODOP:Spring alternative is fxSolver, which is free. Other great apps like ODOP:Spring are Calc98, Engineering Calculator, Freescale RF Engineering Tools and Electrical Engineering Calculators.