A run/walk plan alternates a set time of running with a set time of walking, such as 4 minutes running and 1 minute walking, repeated from start to finish. This run walk pace calculator turns your intervals and the pace you run and walk at into an average pace and a finish time for any distance, and shows how many run/walk cycles that takes.
The average pace is weighted by distance, not by time. With 4:00 running at 10:00 per mile and 1:00 walking at 15:00 per mile, each 5-minute cycle covers 0.4 miles running and about 0.07 miles walking, so the average is 10:43 per mile. Averaging the two paces by time gives 11:00 per mile, which is too slow: the walk takes a fifth of the time but covers only about 14% of the distance.
At that 10:43 average a half marathon takes 2:20:27 and a marathon 4:40:55. Shorter intervals work the same way: 1:00 running at 9:00 per mile and 0:30 walking at 16:00 per mile averages 10:32 per mile, a 32:44 5K.
A reason people use run/walk is that regular walk breaks let them keep a steadier run pace for longer. Enter the intervals you want to compare, such as 4:00 and 1:00, 2:00 and 1:00, or 1:00 and 0:30. Set the walk interval to 0 to run the whole way: the average is then exactly your run pace.
Results are estimates; individual results vary. To turn the finish time into a split for every mile or kilometer, use the half marathon or marathon pace calculator.