The half marathon is the most-run race distance in the world, and the most rewarding to train for. Hard enough to demand structure. Forgiving enough that the build does not consume your life. Smart Runner's half marathon training plan shapes around your goal, your timeline, and your weekly mileage from the first run on.
How long should a half marathon training plan be?
It depends on where you start.
- 8 weeks is enough if you can already run 10 km comfortably and just need a focused build.
- 10-12 weeks is the sweet spot for most runners. Long enough to introduce specific threshold work, short enough to stay focused.
- 16 weeks is right if you are coming back from a layoff or training for your first half.
Smart Runner picks the plan length from your race date and current weekly distance.
What changes vs marathon training?
The half marathon demands a higher fraction of work at threshold pace than the marathon does. The race itself sits very close to lactate threshold for most amateur runners, so tempo and cruise-interval work are the highest-priority weekly session.
The long run still matters, but the longest training run rarely exceeds 22-25 km. Above that you are training for a different race.
Peak weekly mileage typically lands between 40 and 65 km, depending on your goal. A first-half plan peaks around 40-45 km. A sub-1:30 build often peaks at 60-70 km.
Three half marathon goals, three plans
Your first half marathon
Get to the start line healthy. Mileage builds gradually. Long runs progress to 18-20 km. Quality work is light: strides, the occasional progression run, a couple of threshold sessions in the back half of the build. Pace targets are conservative.
Sub-2 half marathon
The most common goal. Threshold pace becomes ~5:35/km. Plan includes weekly tempo, marathon-pace work on long runs, and one VO2max session in peak weeks. Peak mileage 50-60 km. Smart Runner will tell you if your VDOT supports the goal.
Sub-1:30 half marathon
Threshold pace ~4:00/km. Threshold work is non-negotiable. VO2max intervals every week. Long runs include race-pace blocks. Peak mileage 60-75 km. Recovery becomes the limiting factor; the plan watches your ATL/CTL/TSB to avoid digging too deep.
Apple Watch and the half marathon
The half marathon is the race the Apple Watch was built for. Sub-3 hour battery, dual-frequency GPS, structured workout playback. No power-saver tricks required. Smart Runner pushes the full workout structure to your Watch: warm-up, work intervals at the right pace, recoveries, cool-down. Pace appears as a target band, not a noisy instant number.
If you want to read more, our guide on marathon training on Apple Watch covers the platform details, all of which apply to halves.
What if you do not have a recent race result?
Use a recent 5K or 10K time. If you have nothing recent, do a 10K time trial in week 2 of the build, or skip it and let the app start in volume-building mode. Your VDOT updates automatically the moment you log a race result.
Free download. Free trial. No subscription required.
Smart Runner is free to download and free to try for 14 days. After that, pick the lifetime purchase or the annual plan. Either way, your training history stays on your device, and every feature stays unlocked.