RACE PREPARATION
How long do I need to train for a half marathon?
A 12-week half-marathon plan assumes you already run regularly
Twelve weeks is one established half-marathon plan length, but it is not a start-from-zero guarantee. Choose opening weeks you can manage now, and add base-building time if necessary; the plan’s week count is not the whole preparation period.
Read week one before the finish-time promise
Training plans often advertise a duration and a goal, but their starting assumptions matter just as much. Check the number of weekly runs, total distance, longest outing and whether faster work appears immediately. If those demands are already a large jump, you need preparation before the plan.
For example, the Boston Athletic Association’s level-one half-marathon plan runs for 12 weeks and begins with four running days, including a five-mile long run. The word beginner in a race plan does not necessarily mean someone who has never run. Always inspect the actual opening workload.
Compare the plan with a recent normal week
| Area | Your recent routine | The plan’s first weeks |
|---|---|---|
| Frequency | How many days you consistently run | Required running days |
| Duration or distance | A typical completed total | The initial weekly total |
| Longest outing | A run you recover from normally | The opening long run |
| Intensity | Familiar workouts | Any new demanding sessions |
Fill both columns from real information. Do not use your best-ever week as the baseline or quietly omit recent missed weeks. The comparison should help you choose a suitable plan, not persuade you that any plan can fit.
Distinguish completing the distance from racing it
Finishing with a comfortable run–walk strategy and pursuing an aggressive time target require different decisions. Your current experience, available training time and recovery should shape the goal before you choose target paces.
A half marathon is 21.0975 km. At 6:00 min/km, covering that distance takes about 2:06:35. That calculation is useful for planning time on your feet, but it does not prove that you can sustain the pace. A short recent run is only one piece of evidence.
Practise the longer-run logistics
As outings lengthen, rehearse food, fluids, clothing and route access. Choose routes where you can shorten the session if needed. An early experiment with fueling gives you time to refine it; trying everything for the first time during the final long run leaves less room to learn.
Leave flexibility for an interrupted week. Cramming missed mileage into the next weekend changes the workload more than the plan’s printed weekly total suggests. Adjust the timeline or goal rather than treating the schedule as a debt to repay.
Review readiness with more than one number
In Runome, inspect recent consistency, long-run duration and comparable effort data. A race prediction is an estimate based on its inputs, not proof that the preparation is complete. The ability to repeat training and recover matters alongside any predicted finish time.
Use a race-time estimate as a scenario and a worked pace example to understand checkpoints. If the opening weeks of your chosen plan do not fit, build a manageable running routine first. That extra time is part of preparation, not a failure to follow the plan.