Like many others, I have been a long time user and advocate of the McMillan Running Calculator. However, Jack Daniels has just put out his own online running calculator which builds on and is based on the formulas, theories and approach in his highly regarded book Daniels Running Formula.
Similar to McMillan, it allows you to quickly calculate the appropriate training paces for various workouts necessary to help you reach your goals. The calculator also provides equivalent race performances. One big difference is that you can use it to calculate how much conditions like wind, temperature or altitude had on your performance or will have on an upcoming workout or future race and can also be used if you’ve run a race and want to find out what effect wind, temperature or altitude had on your performance.
Another big advantage is that you can enter custom distances to calculate from instead of just the standard distances. For example 7.5km or any distance that you may have run in training/time trial.
Interestingly it calculates that my 26:54 over 7.5km @ Deepwater Point eqautes to a 17:33 5km time which would be a 8 sec PB.
I haven't played with or tested the wind, temperature, altitude aspect of it yet. My own personal observation in the past has been that Americans in particular, seem to over estimate the impact of warmer temperatures on performance, whereas it is something we are just used to.
Anyway, here is the link which can also be found in the sidebar of this blog.
(It works fine on Google Chrome and also Safari on my iPhone but having a bit of difficulty on Internet Explorer at the moment).