# who created the calculators and tables so wrong….or stupid?

Well……let’s talk about that. A race calculator is nothing more than a mathematical algorithm that multiplies a race time by a fixed factor (ratio) to get a projected time for another race. For instance, most race calculators use a ratio in the range of 4.6-4.7 to predict a marathon time from a 10k time, or vice versa. (The calculators’ algorithms result in other fixed ratios for other race distances.) RW calculator’s algorithm produces a ratio of 4.6 to relate 10k and marathon distances. Merv’s calculator uses 4.67. Glover’s tables in his book, “The Competitive Runner’s Handbook”, use a ratio of about 4.7. The tables in Daniels’ book, “Daniels Running Formula”, use about 4.6. Thus, I think that it’s clear that 4.6-4.7 is the range used by most “experts” for marathon/10k relationship. In fact, in the 80’s….before the advent of the internet helped to make the use of running calculators so readily available and popular….a RW article suggested that runners simply use a factor of 4.