As my next half marathon, The Tinkerbell Half Marathon is quickly approaching I like to analyze my current time based on my goal time and what I need to do to accomplish such a goal. I have tried numerous apps, spreadsheets, and various websites. As this link has been shared many other sites, I too am happy to pass along the wisdom! Click on the image to access the best run/walk calculator on the web. This calculator allows you to determine various run/walk ratios to allow you to finish in a certain time.