This marathon pace chart lists every finish time from 2:30 to 6:30 in five-minute steps. Find your goal time in the first column and read across: the pace you need per mile and per kilometer, then the time you should see on the clock at 5K, 10K, halfway and 30K if you run an even pace.
A marathon is 42.195 kilometers, or about 26.2 miles, so small differences in pace add up. Holding 9:09 per mile gives a 4:00 finish; 9:32 per mile gives 4:10. Twenty-three seconds a mile becomes about ten minutes over the full distance.
On race day, pick the row for your goal and note the 5K, 10K and halfway times; a pace band or a note on your arm works well. Check the clock at each marker. Being more than a minute ahead of the chart at 10K usually means you started too fast, and that time tends to come back with interest in the last 10K.
The chart moves in five-minute steps. For a goal between rows, such as 3:52:30, use the marathon pace calculator: it gives the exact pace and a split for every mile or kilometer.
Every time in the chart assumes an even pace from start to finish. Hills, a crowded start and water stops make perfectly even miles rare, so treat each split as a checkpoint to be close to rather than a number to hit to the second. Check splits against the course's mile or kilometer markers rather than your GPS watch: courses are measured along the shortest route a runner could take, and few runners follow it exactly, so watches usually read a little long.