Half marathon training plan
Your half marathon plan, built from the runs you already do
Thirteen miles is long enough that the plan has to respect where you start. Masir sets your first week from your real mileage, then builds the long run and the load step by step.
What a week looks like
| Session | What it is |
|---|---|
| Easy runs | Most of your miles, at conversation pace. |
| Threshold or goal-pace work | Blocks at the effort you will hold on race day, growing as the plan advances. |
| Long run | The key session. It grows gradually and stays slower than your easy pace. |
The week before the race, the long run is capped well below race distance, and nothing long is scheduled in the last five days, whatever day your race falls on. If you start a plan with little time before the race and no time goal, Masir prescribes a more conservative race pace instead of pretending the preparation was complete.
How fast the long run should be
Slower than most runners think. Here is the range for six 5K times.
| Your 5K time | Long run pace /mile | /km |
|---|---|---|
| 20:00 | 8:07 – 9:10 | 5:03 – 5:42 |
| 22:30 | 9:04 – 10:13 | 5:38 – 6:21 |
| 25:00 | 10:01 – 11:16 | 6:13 – 7:00 |
| 27:30 | 10:56 – 12:18 | 6:48 – 7:38 |
| 30:00 | 11:52 – 13:19 | 7:22 – 8:16 |
| 35:00 | 13:41 – 15:18 | 8:30 – 9:30 |
Calculated with Jack Daniels' VDOT formulas, for a flat route in cool weather. For any other race time, use the pace calculator.
When the week does not go to plan
A printed plan assumes you run every session on the day it says. Masir asks what happened instead.
Missed a session: you choose to move it, lighten it or skip it, and the week is reorganized around that choice. There is nothing to catch up.
Sick, injured or on vacation: you pause the plan. The sessions of the break are removed, and training restarts at a reduced volume.
Tired: when your runs feel harder than they should, the load stops climbing until you are back on track.
Runs you do outside the plan count toward the week's load, weighted by how hard they were, so an extra race or a group run does not get stacked on top of a full week.
A plan that starts from your real runs
Masir reads up to twelve months of runs from Apple Health, sets your paces from your current fitness and reorganizes the plan when you miss a run, get sick or go on vacation. Each time, it tells you what changed.
Build my half marathon planiPhone, iOS 17 or later · no account, no ads · free beginner program · full plans with Masir Plus, two-week free trial
Questions
How long is the half marathon plan?
It follows your race date, up to 24 weeks. With twelve weeks or more, the last two are a taper.
What if it is hot on race day?
Training paces are adjusted for heat and humidity, so a warm day does not turn an easy run into a hard one.
Do I need an Apple Watch?
No. Masir reads runs from Apple Health, so any watch that writes there works, including Garmin, COROS and Polar. You can also enter runs by hand or record them with your iPhone's GPS. There is no Apple Watch app.
Is the plan written by a human coach?
No. The plan is calculated by the app from your runs, and it explains every change it makes.