Free Online Calculators

Fatigue Calculator

http://www.fatiguecalculator.com - This website contains a useful set of web-based fatigue analysis software tools for computing fatigue lives of metallic machine components and structures.  The site is free to use and provides data on most steels and aluminum alloys.

 

Heat Transfer

http://www.thermal-wizard.com - Free online calculators that solve common heat transfer problems.  Developed and maintained by MAYA Heat Transfer Technologies.

 

Units Conversion

http://www.onlineconversion.com - Convert from just about any imaginable unit.

 

Misc. Engineering Calculators

http://www.calculatoredge.com/ -The website features hundreds of calculators for solving equations and formulas in field of Electrical, Mechanical, Chemical, Electronics, Civil, Metallurgy, Oil & Gas, Optical, Plastics, Ceramics, Physics, Maths and  more..

 

http://www.efunda.com/calculator.cfm - Includes a list of calculators by categories of finance, design, mechanics, and mathematics. Also includes Engineering Design Aids and a Unit Conversion Calculator

 

http://www.diracdelta.co.uk/ - Contains a substantial collection of online calculators related to aerodynamics, acoustics, civil engineering, electronics, mathematics, mechanical engineering, vibration, optics, physics & signal processing.

 

http://www.hssconnexonline.com/ - Online connection calculator for Hollow Structural Sections in structural design.

 

http://http://www.engineersedge.com/ - Miscellaneous enginering calculators and reference tables.