Sub-42:30 10K
A sub-42:30 10K means holding 6:50 per mile (4:15 per kilometre) for 6.2 miles — a 48.4 VDOT performance. It is a clean, honest benchmark: long enough that you cannot fake it, short enough that one good training block moves it.
Mile-by-mile splits for 42:30
A 10K gives you no room for a strategic error and just enough room for a tactical one. The even-split table holds 6:50 per mile to a 42:30 finish, with 21:15 at 5K. The most common way to miss this goal is to run the first mile eight seconds fast and spend miles four through six paying for it at compound interest.
The negative-split table opens at 6:54 per mile, turns 5K in 21:28, then closes at 6:46. For most runners this is the higher-percentage race: the opening pace feels controlled rather than committed, and the finish is a decision you get to make rather than one made for you.
Even splits — 6:50 per mile
| Mile | Pace | Split | Elapsed |
|---|---|---|---|
| 1 | 6:50 | 6:50 | 6:50 |
| 2 | 6:50 | 6:50 | 13:41 |
| 3 | 6:50 | 6:50 | 20:31 |
| 4 | 6:50 | 6:50 | 27:22 |
| 5 | 6:50 | 6:50 | 34:12 |
| 6 | 6:50 | 6:50 | 41:02 |
| 6.2 | 6:50 | 1:28 | 42:30 |
Even pacing: 6:50 per mile for all 6.2 miles, finishing in 42:30.
Slight negative split — 6:54 out, 6:46 home
| Mile | Pace | Split | Elapsed |
|---|---|---|---|
| 1 | 6:54 | 6:54 | 6:54 |
| 2 | 6:54 | 6:54 | 13:49 |
| 3 | 6:54 | 6:54 | 20:43 |
| 4 | 6:47 | 6:47 | 27:31 |
| 5 | 6:46 | 6:46 | 34:17 |
| 6 | 6:46 | 6:46 | 41:03 |
| 6.2 | 6:46 | 1:27 | 42:30 |
One percent either side of even: 6:54 per mile through halfway (21:28), then 6:46 home. Same 42:30 finish. The mile that straddles halfway blends both paces.
Per kilometre — 4:15 per km
| Km | Pace | Split | Elapsed |
|---|---|---|---|
| 1 | 4:15 | 4:15 | 4:15 |
| 2 | 4:15 | 4:15 | 8:30 |
| 3 | 4:15 | 4:15 | 12:45 |
| 4 | 4:15 | 4:15 | 17:00 |
| 5 | 4:15 | 4:15 | 21:15 |
| 6 | 4:15 | 4:15 | 25:30 |
| 7 | 4:15 | 4:15 | 29:45 |
| 8 | 4:15 | 4:15 | 34:00 |
| 9 | 4:15 | 4:15 | 38:15 |
| 10 | 4:15 | 4:15 | 42:30 |
Even pacing in metric: 4:15 per kilometre across 10.0 km.
Are you ready for a sub-42:30 10K?
| Distance | Equivalent time | Pace /mi | Pace /km |
|---|---|---|---|
| 5K | 20:30 | 6:36 | 4:06 |
| 10K — your goal (42:30) | 42:30 | 6:50 | 4:15 |
| Half Marathon | 1:34:08 | 7:11 | 4:28 |
| Marathon | 3:15:57 | 7:28 | 4:39 |
Equivalent times are computed from the rounded VDOT of 48.4, so the 10K row lands within a few seconds of 42:30 rather than exactly on it. That is rounding, not a different prediction.
To break 42:30 for 10K you need 6:50 per mile, which means you should be racing about a 20:30 5K, which projects to a 1:34:08 half marathon. The 10K is the most honest distance in the sport for exactly this reason: it is too long to sprint and too short to hide in, so the time you run is very close to the fitness you have.
The useful detail is how race pace compares to threshold: 6:50 per mile against a threshold pace of 7:02. Sitting that close to threshold for 6.2 miles is trainable in weeks rather than seasons — tempo runs at 7:02 and intervals at 6:30 both move it directly. This is the goal most likely to fall within a single well-run eight-week block, provided the easy days stay easy at 8:27.
Sub-42:30 is the first rung on the far side of the forty-minute wall, and it has its own clean metric identity: 4:15 per kilometre, on the nose. Its nearest relative is not another 10K at all — the equivalent 5K here is 20:30, which puts the sub-20 5K and this goal in the same season's work, moved by the same sessions: threshold at 7:02, intervals at 6:30. Racing it is a patience exercise with a short fuse — even through 21:15 at 5K, then a decision every kilometre. Clear it convincingly and 40:00 stops being a wall and becomes a schedule.
Where do you stand right now?
Enter a race you have actually run and this will tell you where you stand against the 48.4 VDOT a sub-42:30 10K requires — your score, the target, and the gap. Nothing is stored or sent anywhere.
Training paces for a sub-42:30 10K
These are the paces that go with the 48.4 VDOT a sub-42:30 10K requires. Treat them as day-one numbers — they should change as you do. The most common mistake is running the easy days too hard: 8:27 per mile is not a suggestion, it is what makes the quality sessions possible.
| Pace | min/mi | min/km | Where it is used |
|---|---|---|---|
| Easy | 8:27 | 5:15 | Most of your week |
| Marathon | 7:28 | 4:39 | Race-pace work |
| Threshold | 7:02 | 4:22 | Tempo / cruise intervals |
| Interval | 6:30 | 4:02 | VO₂max work |
| Repetition | 6:05 | 3:47 | Speed and form |
| Recovery | 10:14 | 6:22 | Shake-out jogs |
Easy pace is a range rather than a point — Daniels defines it as 59–74% of VO₂max, which for the fitness behind a sub-42:30 10K runs from 8:05 to 9:41 per mile. The single easy figure below is the 70% value.
Paces that move when you do.
The table above is a static snapshot of the VDOT 48.4 behind a sub-42:30 10K. Why Not recalculates the same six paces after every run you log — pulling them tighter as you get fitter, easing them off when you are cooked, and rebuilding the plan around the weeks life actually gave you.
Build my sub-42:30 planSub-42:30 10K FAQ
6:50 per mile, or 4:15 per kilometre, for 6.2 miles, passing 5K at 21:15. Opening at 6:54 and closing at 6:46 reaches the same 42:30.
VDOT 48.4 — and every pace and equivalent time on this page is derived from it.
Often a single eight-week block if you are within a couple of minutes. Race pace of 6:50 sits close to your threshold pace of 7:02, and threshold is the fastest-responding system in distance running.
Roughly a 20:30 5K. That is the equivalent performance at VDOT 48.4.
Easy at 8:27 per mile (range 8:05 to 9:41), marathon pace at 7:28, threshold at 7:02, intervals at 6:30, repetitions at 6:05, recovery at 10:14.
Every number on this page is computed from our own implementation of the Daniels–Gilbert formulas published in Daniels' Running Formula (Jack Daniels & Jimmy Gilbert) — the same library the Why Not app runs. Nothing is transcribed from the book's tables, and this site is not affiliated with or endorsed by the authors. Equivalent times assume you train appropriately for the target distance; that caveat is Daniels' own.
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A human marathon coach runs $100 to $300 a month and rebuilds your plan when you email them. Why Not runs the same Daniels VDOT engine behind every number on this page and adapts after every workout. A full year of the app costs less than the cheapest month of human coaching.
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