To run a 3-hour marathon, you need to maintain a pace of 6 minutes and 50 seconds per mile or 4 minutes and 15 seconds per kilometer. This pace would give you a predicted finish time of 2 hours and 59 minutes and 10 seconds. However, its important to note that unless you run the shortest distance racing line throughout the marathon, you will end up running slightly longer than 26.2 miles, which will affect your finish time.

According to, the tempo pace for a sub-3 hour marathon should be between 6 minutes and 15 seconds and 6 minutes and 30 seconds per mile. This pace should be faster and harder than what youll do on race day. Long runs are also important to help acclimate your body to long distances, and you should target about 30-40 miles per week.

Its also important to have a well-structured training plan that includes easy, long, tempo, and speed runs, as well as core sessions, a rest day, and optional cross-training. The training plan should be at least 16-18 weeks long, and you should be able to run 30-40 miles per week out of the gate.

In summary, to run a 3-hour marathon, you need to maintain a pace of 6 minutes and 50 seconds per mile or 4 minutes and 15 seconds per kilometer. You should also have a well-structured training plan that includes easy, long, tempo, and speed runs, as well as core sessions, a rest day, and optional cross-training.