Timed Race Chart
From Fellrnr.com, Running tips
This form will generate a pace chart for timed races, such as 24 hour races. This chart is a table with the a row for the number of laps completed, and a column for each pace. Simply look down to find out how many laps you've completed, and then go across until you find the time that has elapsed. You will then see what your projected pace is for the race.