These are all simple and manual calculators. I strongly recommend deepening your reading. The key things to research are Sample Size determination and Chi-Square tests for statistical significance. Here are the calculators:


http://www.splittestaccelerator.com/freetool.php

http://www.splittester.com/

http://answersresearch.com/calculators.php

http://www.surveysystem.com/sscalc.htm