The 10K is 10 kilometers, about 6.21 miles. It rewards patience: an even pace from the start is almost always faster than banking time early.
Enter a goal time to get your target pace, or your usual pace to see the finish time it gives. The splits table lists where you should be at every mile or kilometer.
For example, a 50:00 10K is 5:00 per kilometer, or about 8:03 per mile, the same pace as a 25:00 5K held for twice as long.