Ask the Race Director: Net Time vs Gun Time?
Ask the Race Director: Gun Time vs. Net Time — What’s the Real Finish Time?
By John Mortimer, Millennium Running
Let’s play out a hypotheical scenario that could confuse even the most seasoned runner…
You’re watching the Boston Marathon on Patriot’s Day. The announcer’s voice echoes through Boylston Street:
“Winning this year’s Boston Marathon – The Greatest Runner of All Time – From Kenya – Eliud Kipchoge”
The crowd roars. Kipchoge surges ahead in the final stretch and crosses the finish line in a blazing 2:04:00. Confetti, TV cameras, photographers—it’s a classic marathon finish.
But here’s the twist…
About 20 minutes later, the official results are published online. And surprisingly, Kipchoge is listed in second place.
What happened?
Unbeknownst to the crowd or the media, a runner named “Miles” started back in the pack, 4 minutes behind the official start due to his assigned corral. He worked his way up the field over 26.2 miles and crossed the finish line with a net time of 2:03:00 — a full minute faster than Kipchoge’s.
So, who’s the real winner?
Who gets the prize money and the title?
Let’s break it down.
Gun Time vs. Net Time: Explained
John Mortimer, Millennium Running’s founder, sheds some light on how race timing works and why this seemingly strange outcome is actually standard across the running industry.
“At nearly all professionally timed races — including ours — every runner receives two finish times: Gun Time and Net Time,” explains Mortimer. “And yes, there’s a big difference.”
Here’s how it works:
Gun Time (a.k.a. Official Time)
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Starts when the starting horn or gun goes off.
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This is the time used to determine overall winners, podium finishers, and prize money recipients.
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Everyone in the race, regardless of when they physically cross the start line, shares the same Gun Start Time(called Scratch Time in the industry).
Net Time (a.k.a. Chip Time)
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Begins when a runner actually crosses the start line mat, using a chip attached to their race bib.
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Stops when the runner crosses the finish line mat.
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Net Time is used for personal records, age group rankings, and most amateur race results.
Why the difference?
In large races like the Boston Marathon or Millennium Running’s events, thousands of runners are separated into starting corrals. It might take several minutes (or more) to physically reach the start line. That’s where chip timing — using RFID tags and GPS-synced timing systems like MyLaps — allows for personalized, accurate Net Times.
How It All Gets Timed
Each runner in a Millennium Running event has a chip embedded in their bib number. As they step over mats at the start and finish, their unique RFID code is captured with to-the-thousandth-of-a-second accuracy. These systems log three key time stamps:
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Scratch Time – The official race start time (Gun Time base)
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Start Time – When the runner crosses the start mat
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Finish Time – When the runner crosses the finish mat
The formulas:
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Gun Time = Finish Time – Scratch Time
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Net Time = Finish Time – Start Time
These times are uploaded from decoder boxes at the mats and processed by the scoring system. Most races will display Net Time first in the results, especially for mid-pack and age group runners — but the Gun Time still determines the overall winner.
So Who Wins — Kipchoge or Miles?
Back to our Boston Marathon scenario. While “Miles” ran a faster Net Time from start to finish, Kipchoge crossed the finish line first, and that’s what matters for the win.
Industry standard (and USATF rules) are clear: The first runner to cross the finish line wins, regardless of chip time. That’s why prize money and podiums are based on Gun Time.
That said, runners in age group divisions, Clydesdale/Athena categories, or charity teams are almost always ranked by Net Time — because those divisions emphasize personal performance over head-to-head racing.
Why It Matters
Understanding the difference between Gun Time and Net Time helps set realistic expectations — especially for newer runners.
“You might finish as the 1,000th person across the line but rank 1,200th overall based on Net Time,” says Mortimer. “That’s because 200 runners who started after you ran faster start-to-finish.”
In today’s chip-timed world, it’s less about when the gun goes off and more about how well you run your own race. Chip timing ensures every runner is measured fairly and accurately — regardless of where they start in the pack.
Final Thoughts from John Mortimer
“It’s a beautiful thing, really. With chip timing, every runner — from the elites up front to the final finishers — can track their exact performance. And for most runners, that’s what matters most.”
So next time you see a finish time discrepancy, don’t panic. Just remember:
🏆 Gun Time = who wins the race
⏱️ Net Time = who ran it best, on their terms
Whether you’re chasing prize money or a new PR, both times tell part of your story. And thanks to chip timing, every story is captured with precision.
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