How Are Marathons Timed?

Are you wondering, “how are marathons timed?” before the big day? Fortunately, with chip timing, measuring a marathon runner’s time is more accurate than ever. 

When you finish your first marathon, it will likely be one of the biggest achievements of your lifetime, but the reality is that you may not cross the start line until 20 minutes into the race if you’re running in a marathon with thousands of other runners. For seasoned marathon runners, having an accurate time is essential. Today marathons are timed with chip timing, meaning participants wear RFID tags during the race to give exact figures.

Old-School Timing Methods

In the early days of marathons, you may have experienced gun timing. With gun timing, the clock starts for all the runners when the gun is shot. It doesn’t matter when you end up crossing the start line; you’re still measured from the time the shot sounds. 

How Are Marathons Timed
Race organizers stayed with this timing method even though it was wildly inaccurate

For a long time, race organizers stayed with this timing method even though it was wildly inaccurate. The reason is that they were trying to uphold the competition’s integrity. 

Chip Timing

With chip timing (also called net timing), you get a more accurate race time because timing systems use RFID transponder chips that precisely measure the times of the runners. During the race, the marathon runners wear the RFID tags in various ways, whether as ankle bracelets, shoelace tags, or disposable race bibs with UHF RFID tags affixed. 

Marathon Lima 42k
Marathon runners wear the RFID tags in various ways like bracelet

When you run across specialized RFID timing mats, your race chip registers; timing starts when you pass over these mats at the start line. When you get to the finish line, you’ll also run over RFID timing mats. 

You might also be interested in our explainer on why are marathons so expensive.

FAQs About How Are Marathons Timed

How Long Is A Marathon? 

Marathons are 26.2 miles long. Elite marathon runners can finish a marathon in as little as two hours, but the average can vary by age group and other demographics. 

How Do I Calculate My Marathon Time?

When registering for a marathon, you may be asked what your approximate finish time and pace time will be. If you’ve never completed a marathon, the best way to estimate your finish time is with a marathon pace calculator

Is There A Time Limit On Marathons?

Because large marathons usually have to close roads, most marathons have a time limit. In most marathons, the time limit is between six and eight hours, with the course closing on a rolling schedule.
After the time limit, racers aren’t allowed on the course once the streets are reopened to vehicles.