Before running your marathon, it's definitely helpful to have a rough estimate of your marathon finishing time, so you know how to pace yourself properly. But predicting race times, especially for marathons, can be tough because there are so many variables, such as weather and course conditions. A quick formula that a lot of runners like to use is to take a recent half marathon time, double it, and then add 10-20 minutes, depending on the difficulty of the course.
You can also use race time prediction calculators to determine your marathon time, based on a recent race. For the most accurate prediction, you should use a race time from a race you've done about 4-6 weeks before your marathon.
Here are a couple of good race time prediction calculators to try:
Running for Fitness Race Predictor: Just plug your age, gender, and time/distance from a recent race into the calculator to find out how you might perform in races at other distances. This calculator shows several different predictions, based on different formulas. So you get a range of predicted times, and you can see that it's not an exact science -- just an estimate.
MarathonGuide.com Race Results Prediction: Choose a distance and a time to calculate theoretical race results at different distances and check out your marathon prediction.
Once you have an estimated finishing time, you can use a Pace Calculator to figure out the average pace for that time.
Can I Really Run that Predicted Marathon Time?
Keep in mind that a predicted marathon time is not a guarantee. You have to do the appropriate endurance training for a marathon, and there are lots of other factors -- course difficulty, weather conditions, nutrition and hydration, how you're feeling -- that come into play. In most cases, only experienced marathoners achieve their predicted time or very close to it. If you're running your first marathon, focus on completing the race and finishing strong. Regardless of your time, finishing a marathon is an incredible achievement. If you're looking for a ballpark finishing time prediction for your first marathon, add 5-6% to the calculator prediction.
If you're curious where you might end up finishing (top 25%, age group winner, etc.) in a particular marathon, look at the online results from last year's race. The range of finishing times and the number of participants will probably be similar this year.
Some marathons do have time limits, such as six or seven hours (although others have no limit). So, if you're a slower runner or walker, be sure to find out if there's a cut-off time when picking a marathon.
Also see: Marathon Training Schedules
Frequently-Asked Marathon Training Questions
Celebrity Marathon Times
Am I Ready to Train for a Marathon?
What is a Good Time for a Marathon?
How Long Does It Take to Train for a Marathon?
Other Race Distances: How Long Does it Take to Run a 5K? l How Long Does it Take to Run a 10K? l How Long Does it Take Run a Half Marathon?