From Institute of Spring Technology:
IST's spring design software is available for compression, extension, torsion, rectangular wire compression, conical compression, non-standard compression, disc and spiral springs. You can validate an existing design or automatically calculate the lightest spring that meets your needs. Designs and tolerances are calculated to EN, SMI, BS, DIN, JIS and IS standards (as applicable), and the software and printouts are available in English, French, Spanish, German and Italian as standard. Metric and Imperial units are available. Where data is available, you can view fatigue life and relaxation predictions for your design, as well as spring drawings and load/length graphs.