The major difference between a marathon and a half-marathon is 13.1 miles. A marathon covers 26.2 miles, usually around a city either in a big loop with the start and finish close together or with a start in one area and a finish in another. A half-marathon is 13.1 miles and often is run as just that -- half of a marathon race. There are, however, major differences in training for and running these events.
Paired Events
Some marathons are separate races, while others are paired with half-marathons. The two races may start at the same place and follow the same course, but have a turnaround point at which half-marathoners turn back to the finish line while marathoners keep running. Sometimes the two races start at the same time; other events have separate starts so runners don't mingle.
Training
Training for a full marathon requires more time and more running distance. Typical marathon training programs cover from 18 to 32 weeks, while half-marathon training is about eight to 12 weeks. Marathon workouts include more long runs, working up to 20 to 26 miles in the weeks immediately preceding the race. Half-marathoners rarely run more than 10 or 12 miles in training.
Which to Choose?
Many runners try a half-marathon to see if they want to try or are up to the longer distance. You shouldn't consider either event unless you can run 15 to 20 miles a week comfortably. Intermediate runners should expect to train 25 or more miles a week for a marathon, including weekly long runs up to 20 or 26 miles. Half-marathons require similar weekly mileage but with fewer long runs. Marathons require more cardiovascular endurance and more "tapering" in training in the final pre-race days.
Race Size
Major marathons are huge races, with thousands of participants. The Chicago Marathon, for instance, registers about 45,000 runners. You'll run in a crowd the entire 26.2 miles. Half-marathons usually are much smaller, especially if they are not paired with a marathon. A marathon may take three and a half hours or more for an intermediate runner to complete, a half usually two hours or so for a comparable runner.
