To predict your race time for an upcoming race you can use the Riegel formula and apply to a recently completed race. While this formula gives you a good approximation there are a few caveats.
Have you ever tried to finish a race under a time limit? This calculator will help you determine the average pace you should run at to reach your goal. Maybe a marathon under 3 hours? Or a 5K under 25 minutes?
This calculator will help you to predict your race time based on a previously completed race. It is based on the formula created by Peter Riegel. For details on the formula and the math read the how to guide.