Pace Calculator

The Riegel exponent of 1.06 is calibrated for trained runners across distances from 1 mile to marathon. It tends to overpredict marathon times for runners who have not built marathon-specific endurance, and underpredict for ultra distances. For races within 2-3x of your known distance, expect predictions within 3-5%.

It depends on your sex, age, and training history. As a rough field guide for healthy adult runners with at least a year of consistent training, 10:00/mi is a solid recreational marathon pace, 8:00/mi is competitive amateur, and sub-7:00/mi puts you in the local elite range. Boston qualifying times range from 7:00/mi to 9:00/mi depending on age group.

Pick one and stick with it. Your perceived effort, your watch, and your route signage should all match. American runners default to miles, most of Europe and Asia uses km. Switching mid-cycle introduces small math errors in pace targets that compound across a training block.