Consider the time element as well. You may run 60 miles a week, but a 20-mile run may take you 3:20 and a 16-mile run may take you 2:40. A 3:20 pace is fairly fast for running that distance, so if you're not used to going that fast, you might want to start out with some shorter runs first. In general, a mile takes about 30 minutes to run. So, 16 miles would take us around 5 hours. That's a pretty solid effort for such a long run! However, there are many factors at play here. The distance of your run will determine how long it takes you to jog it. A 20-mile run will take much longer than a 10-mile run. Your fitness level also plays a role in how long it takes you to run a certain distance. If you're very fit, you can run farther before feeling tired. If you're not as fit, you'll need to stop earlier to avoid injury. The weather also affects how long it takes you to run a certain distance. If it's hot out or not, if it has rained or not, if it's sunny out or not... all these factors come into play when trying to estimate how long it will take you to jog somewhere between one half and full marathon.