Area ratio is the most important factor that needs to be calculated when designing a stencil to make sure we are selecting the right thickness and stencil type. There are many tools used to get this ratio for smallest aperture instead of using calculator, but most of them are poorly designed! DFS presents the 'Stencil Specs Advisor' which is not just a professionally designed excel tool that provides area and aspect ratios along with some other info like aperture area and solder paste volume generated through the aperture, but it also offers the ability to set the desirable limits for various material types and post processing technology, and advise what stencil type to use based on these criteria.
This is the first version of the tool, and will be subject to improvements based on your feedback. Try it out today! http://www.design-for-success.com/ssadv.htm