Calculating Start Loss, Aid Station Time and Cutoffs | Gun Time vs Net Time and the Pace You Need
A marathon’s official time (gun time) is measured from the starting gun, so if you start from a rear corral, the time it takes you to reach the start line — your start loss — is included in your result. Walking through aid stations to drink also adds up to several minutes. And because cutoff times are counted from the gun too, start loss eats into your margin. This guide explains the difference between gun and net time, how to calculate the pace you need once start loss and aid-station time are included, and how to check how many minutes ahead of each cutoff you will arrive, with worked examples.
Gun time vs net time
A marathon result comes in two forms: gun time (also called gross time) and net time. Gun time runs from the starting gun to when you finish, and many races use it as the official result. Net time runs from when you cross the start line to when you finish, measured by the timing chip on your shoe or bib.
| Gun time | Net time | |
|---|---|---|
| Starts counting | At the gun | When you cross the start line |
| How it is used | The official result at many races | Often shown on the certificate as a reference time |
| Course clocks | Show gun time | — |
| Your watch | — | Same as net if you start it at the start line |
| Cutoffs | Based on gun time (time or clock time from the gun) | — |
The difference between gun and net time is your start loss. At races of a few thousand runners it is 1–3 minutes; starting from a rear corral at a big-city marathon with tens of thousands of runners, it can be 5–15 minutes or more. Many races print both on the certificate, but gun time may be used for official records or corral seeding at the next race, so check the race rules in advance.
The pace you need once start loss is included
If you want to beat a goal in gun time, your net (watch) goal has to be shorter by the amount of your start loss. The pace you need is (goal time − start loss) ÷ distance.
| Start loss | Net goal for sub-4 | Pace needed (per km) | Net goal for sub-5 | Pace needed (per km) |
|---|---|---|---|---|
| None | 3:59:59 | 5:41 | 4:59:59 | 7:06 |
| 3 min | 3:56:59 | 5:37 | — | — |
| 5 min | 3:54:59 | 5:34 | 4:54:59 | 6:59 |
| 10 min | 3:49:59 | 5:27 | 4:49:59 | 6:52 |
| 15 min | 3:44:59 | 5:20 | — | — |
With a 5-minute start loss, a sub-4 in gun time needs 5:34 per km, not 5:41. That is only 7 seconds per kilometre, but for a goal at the limit of your ability it is a big difference. If a sub-4 in net time is good enough for you, ignore start loss and plan at 5:41 per km.
Including time stopped at aid stations
If you take a paper cup at an aid station and walk while drinking, you lose about 10–30 seconds per station. With aid stations every 5 km in a marathon, that is 8 stations: 5, 10, 15… 40 km. Subtract the total stopped time from your goal to get your running time, and divide that by the distance to get the pace you need while running.
| Seconds stopped per station (8 stations) | Total stopped | Running pace (sub-4, per km) |
|---|---|---|
| 0 s (drink on the run) | 0 s | 5:41 |
| 10 s | 1 min 20 s | 5:39 |
| 15 s | 2 min | 5:38 |
| 20 s | 2 min 40 s | 5:37 |
| 30 s | 4 min | 5:36 |
Include both a 5-minute start loss and 15 s × 8 aid stations, and the running pace needed for a sub-4 in gun time is about 5:31 per km. If your race has aid stations every 2.5 km, or you plan a toilet stop, include that too for peace of mind.
Will you make the cutoffs? Your margin counts from the gun
A cutoff means that if you do not pass a set point by a set time, your race ends there. Closing times are set by time from the gun, so the longer your start loss, the smaller your margin. Work out “expected passing time = gun time of day + start loss + net time to that point” and compare it with the closing time.
As an example, take a fictional race with the gun at 9:00 and a 6-hour time limit. You plan for a gun time of 5:50 with a 10-minute start loss and 20-second stops at 8 aid stations. Your running pace is then 8:00 per km.
| Cutoff (fictional example) | Closing time | Expected passing time | Margin |
|---|---|---|---|
| 10 km | 10:35 | 10:30 | 4 min 43 s |
| 20 km | 11:55 | 11:50 | 4 min 06 s |
| 30 km | 13:20 | 13:11 | 8 min 30 s |
| 35 km | 14:00 | 13:51 | 8 min 11 s |
| 40 km | 14:40 | 14:32 | 7 min 53 s |
| Finish | 15:00 | 14:50 | 10 min 00 s |
Even with 10 minutes to spare at the finish, the early cutoffs leave only about 5 minutes. That is because early cutoffs are often set tight, taking the crowding right after the start into account. In the same race, a runner with a 15-minute start loss who tries to run even pace for exactly 6 hours gun time would miss the 10 km and 20 km cutoffs. The more your goal is simply to finish, the more important it is to check your margin at every cutoff, not just the finish time limit.
Calculate it all at once with the Marathon Pace Band Maker
- 1
Enter your goal and start loss
In the “Splits & Cutoffs” tab, enter the distance and goal time, choose whether the goal is gross (gun) or net, and enter your start loss.
- 2
Enter aid-station conditions
Enter the seconds you stop at each aid station and the spacing between stations, and your running pace is shown.
- 3
Enter the gun time and cutoffs
Enter the time of the gun and the cutoffs from the race rules, one per line, like “10 10:35”. You can also enter time from the gun (“10km 1:35:00”).
- 4
Check your margins and print
The expected passing time and margin for each cutoff are shown. Cutoffs with under 10 minutes of margin are yellow; ones you would miss are red. You can also print a pace band with passing times written on it.
For printing, see how to make a pace band; if you want a plan that holds back early, see negative split pacing.
FAQ
- What is the difference between gun time and net time?
- Gun time runs from the starting gun to the finish and is the official result at many races. Net time runs from when you cross the start line to the finish. The difference is your start loss, which can be 5–15 minutes or more from a rear corral at a big race.
- What pace do I need for a sub-4 with a start loss?
- To beat 4 hours in gun time: 5:37 per km with a 3-minute start loss, 5:34 with 5 minutes, and 5:27 with 10 minutes. If a sub-4 in net time is enough, it is 5:41 per km regardless of start loss.
- How much time do I lose stopping to drink?
- Walking while you drink costs about 10–30 seconds per station. Stopping 15 seconds at each of 8 aid stations spaced every 5 km totals 2 minutes; 30 seconds each totals 4 minutes. For a sub-4 with 15-second stops, you need to run 5:38 per km while moving.
- How do I calculate whether I will make a marathon cutoff?
- Calculate expected passing time = gun time of day + start loss + net time to that point, and compare it with the closing time. Cutoffs count from the gun, so start loss reduces your margin. Early cutoffs are often tight, so check each one, not just the finish.
Tools in this article
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