Goal time
Sub-40-minute 10K pace
Forty minutes for 10K is four minutes a kilometer for ten kilometers — the same pace as a sub-20 5K, held twice as long. That is the whole difficulty of it in one sentence.
The pace this target demands
- Finish time
- 40:00
- Per mile
- 6:26
- Per kilometer
- 4:00
- Speed
- 9.3 mph
The time to actually aim at
40:00 is a ceiling, not a target. Plan for 39:40 instead and you get 6:23 per mile, which buys back the seconds a long tangent, a crowded water station or a slow first quarter-mile will cost you.
The paces on this page are shown to the nearest second, which is how a watch shows them. Typing a rounded pace back into a calculator will not return the exact target time, and no amount of decimal places fixes that on a real course.
The arithmetic is trivial and the execution is not. Because the pace is identical to the twenty-minute 5K pace, this target is the clearest test of endurance rather than speed anywhere on this site: runners who can hit one and not the other know exactly which half of their training to fix.
Splits every 1 mi
An even effort from start to finish. Cumulative time is the clock reading as you pass each marker.
Ten kilometer splits, all identical on an even plan. The sixth and seventh are the ones that decide it.
Scroll the table sideways on a narrow screen.
Splits every 1 mi
| Split | Distance | Split time | Cumulative | Pace |
|---|---|---|---|---|
| 1 | 1.00 | 6:26 | 6:26 | 6:26 |
| 2 | 2.00 | 6:26 | 12:52 | 6:26 |
| 3 | 3.00 | 6:26 | 19:19 | 6:26 |
| 4 | 4.00 | 6:26 | 25:45 | 6:26 |
| 5 | 5.00 | 6:26 | 32:11 | 6:26 |
| 6 | 6.00 | 6:26 | 38:37 | 6:26 |
| 7 | 6.21 | 1:23 | 40:00 | 6:26 |
Splits every 1 km
| Split | Distance | Split time | Cumulative | Pace |
|---|---|---|---|---|
| 1 | 1.00 | 4:00 | 4:00 | 4:00 |
| 2 | 2.00 | 4:00 | 8:00 | 4:00 |
| 3 | 3.00 | 4:00 | 12:00 | 4:00 |
| 4 | 4.00 | 4:00 | 16:00 | 4:00 |
| 5 | 5.00 | 4:00 | 20:00 | 4:00 |
| 6 | 6.00 | 4:00 | 24:00 | 4:00 |
| 7 | 7.00 | 4:00 | 28:00 | 4:00 |
| 8 | 8.00 | 4:00 | 32:00 | 4:00 |
| 9 | 9.00 | 4:00 | 36:00 | 4:00 |
| 10 | 10.00 | 4:00 | 40:00 | 4:00 |
Three ways to spend the same time
The finish time is identical in all three. What changes is where the effort goes, and how the opening miles feel.
Scroll the table sideways on a narrow screen.
| Strategy | Opens at | Closes at | First half | Second half | Second half vs first |
|---|---|---|---|---|---|
| Even splits | 6:26 | 6:26 | 20:00 | 20:00 | Level |
| Negative splits | 6:33 | 6:18 | 20:12 | 19:48 | 0:25 faster |
| Positive splits | 6:19 | 6:35 | 19:48 | 20:12 | 0:25 slower |
Even splits
The same pace for every split. It is the plan that needs the least judgment and the one every other plan is measured against, and for a first attempt at a barrier it is usually the right answer.
Negative splits
Set here at 2 percent, which means the opening pace is 2 percent slower than even and the closing pace is 2 percent faster — a spread of 4 percent from the first split to the last. On the clock that is 6:33 out of the gate and 6:18 coming home. It costs discipline early and gives back a second half 0:25 quicker.
Positive splits
The mirror image, and the one that happens by accident more often than by choice. The same 4 percent spread, run the other way round: 6:19 early, 6:35 late. It is a real plan for a course that climbs at the end, and a warning sign everywhere else.
The percentage is the swing at each end, not the difference between the halves. Doubling it gives the spread from the first split to the last.
A negative split at this distance means opening a few seconds slower than target for the first three kilometers. That feels wrong at the time and looks right on the finishing clock.
Clock time at every marker
An even effort, at the points a race actually marks. Worth writing on a wristband.
| Point | Elapsed | Remaining |
|---|---|---|
| 1 km | 4:00 | 36:00 |
| 1 mi | 6:26 | 33:34 |
| 2 km | 8:00 | 32:00 |
| 4 km | 16:00 | 24:00 |
| Halfway | 20:00 | 20:00 |
| 4 mi | 25:45 | 14:15 |
| 8 km | 32:00 | 8:00 |
| 6 mi | 38:37 | 1:23 |
| Finish | 40:00 | 0:00 |
What being off pace costs
Every row starts from the exact required pace and shifts it. This is the table to look at when the first mile comes up quick.
Per mile
| Off pace by | Pace | Finish time | Vs target |
|---|---|---|---|
| 15 s faster | 6:11 | 38:27 | 1:33 inside |
| 10 s faster | 6:16 | 38:58 | 1:02 inside |
| 5 s faster | 6:21 | 39:29 | 0:31 inside |
| Exactly on pace | 6:26 | 40:00 | On the line |
| 5 s slower | 6:31 | 40:31 | 0:31 over |
| 10 s slower | 6:36 | 41:02 | 1:02 over |
| 15 s slower | 6:41 | 41:33 | 1:33 over |
Per kilometer
| Off pace by | Pace | Finish time | Vs target |
|---|---|---|---|
| 15 s faster | 3:45 | 37:30 | 2:30 inside |
| 10 s faster | 3:50 | 38:20 | 1:40 inside |
| 5 s faster | 3:55 | 39:10 | 0:50 inside |
| Exactly on pace | 4:00 | 40:00 | On the line |
| 5 s slower | 4:05 | 40:50 | 0:50 over |
| 10 s slower | 4:10 | 41:40 | 1:40 over |
| 15 s slower | 4:15 | 42:30 | 2:30 over |
The middle row is the definition of the target rather than a way to hit it. Finishing at exactly 40:00 does not beat 40:00, which is the whole reason the aim-for time above exists.
Five seconds a mile moves the finish by about half a minute. Forty minutes does not have a lot of half-minutes to spare.
The targets either side
Every other pace for this distance
The full lookup table for the 10K, from a pace almost nobody holds down to a comfortable one, with finish times for all of them.
A distance that is not on this list?
The web calculator takes any distance, any time and any pace, and works out the rest as you type. Nothing to install, nothing to sign up for.
The app
Take the numbers to the start line
Simple Pace Calculator is a free app for iPhone & iPad. Distance, time, pace and speed stay in sync while you edit any one of them, and a lock shows which value is being held fixed. All calculations work offline.
$2.99 (US), one-time unlocks two extra tools, once, with no subscription: Splits, for even, negative or positive pacing at any interval, and ETA, for working out when a runner reaches your spot on the course.
For this distance the app offers splits every 400 m, 1 km, 1 mi, 1/2, plus a custom interval of your own.
Everything on this page stays free on the web, whether or not you ever install anything.
