Running
Half marathon training plan: from beginner to race day in 16 weeks
Your first half marathon is about patience and a plan, not willpower in the final week.
Where to start
A half marathon training plan usually takes 16–20 weeks from scratch or 10–12 weeks with a solid running base. A week combines easy runs, a long run, a manageable quality session, strength work and rest; the 16-week example below allows extra time to adapt.
1trAIner is an AI coach that builds a half marathon training plan using your watch data and adjusts it after every workout.
- Distance
- half marathon (21.1 km)
- Training timeframe
- 16 weeks
- Price
- 450 ₽ per month or 4999 ₽ per year
Map: capture territory
Runs turn into capturing territory on the map
Video text
The area on the map isn't yours yet. You run a loop around the park — and the land inside the loop becomes yours. You run through a neighbor's section — you take that too. In the runners' ranking you move up to first place.
The first 7 days are free, no card needed. No automatic charges: you renew your subscription manually.
This 16-week training plan prepares you for your first 21.1 km without setting a required finish time. It helps to have an established running routine; if your starting base is limited, the timeline may need to be revised. The main goals are to get used to sustained effort gradually and work out your race nutrition strategy in advance.
The coach in 1trAIner takes into account your level, schedule, and available time for a long run. After connecting Garmin or Apple Watch, data arrives automatically, and the plan is recalculated after every workout. If the new distances feel hard, the next step is adjusted based on the training load you completed.
As you adapt, long runs take more time, while easy sessions help you stay consistent without extra intensity. During workouts you test the gear, fluids, and nutrition you plan to use on race day. Progress shows in your ability to finish longer outings calmly and recover afterward.
How long to prepare
From scratch
Allow 16–20 weeks, or longer if regular walking and running still feel difficult. Start with run-walk sessions; build consistency before distance.
With a running base
If you run regularly and comfortably cover 10 km, allow around 10–12 weeks. A 16-week plan gives you more time to consolidate mileage and recover.
For a target time
With a stable base, allow 12–16 weeks for a time goal. Refine the timeline and pace using a recent 10 km result; one month is only enough for fine-tuning if you already handle the distance.
Weekly structure
- 2–3 easy runs at conversational effort; roughly 80% easy and 20% harder running is a guide, not a quota.
- One quality session with a warm-up and cool-down; add a second only with a stable base, keeping easy days between them.
- One easy long run, gradually reaching 16–18 km when ready; practise drinking and fueling in advance.
- 1–2 short conditioning and strength sessions for legs, calves and core, without fatigue that disrupts the next run.
- At least one rest day; follow the long run with rest or very easy activity according to how you feel.
- A recovery week every 3–4 weeks: reduce mileage and the long run, without making up missed sessions.
Week-by-week plan for runners with a base
This plan is a guide: the AI coach adjusts it to your starting base and recovery. Mileage is an example for regular runners, not a required quota; choose the lower end according to what you can sustain. In each two-week block, the long run and mileage describe the loading week: reduce both by roughly 20–30% every fourth week. Around 10% weekly growth is a reference, not a requirement; do not increase volume and intensity together. Taper over the final 2–3 weeks; race-week mileage excludes the race itself.
| Week | Focus | Key session | Long run | Volume |
|---|---|---|---|---|
| 1–2 | Consistency | Easy running; establish 3–4 manageable runs per week. | 6–8 km | 18–24 km/week |
| 3–4 | Consolidating the base | Short relaxed strides when ready; reduce training in week four. | 8–10 km | 20–26 km/week |
| 5–6 | Building endurance | Extend one easy run slightly while keeping breathing controlled. | 10–12 km | 24–30 km/week |
| 7–8 | Controlled effort | 2 × 8 minutes at moderate effort with 3 minutes of easy jogging between; follow with a recovery week. | 12–14 km | 26–32 km/week |
| 9–10 | Long runs and fueling | Test familiar drinks and fuel during an easy long run. | 14–16 km | 28–36 km/week |
| 11–12 | Sustainable pacing | 2 × 12 minutes at controlled effort with 3 minutes of jogging between; then a recovery week. | 16–18 km | 30–38 km/week |
| 13–14 | Rehearsal and taper | Short race-pace segments; reduce mileage from week 14. | 12–14 km | 24–30 km/week |
| 15–16 | Taper and race | Easy runs and short, familiar strides; rest and race when ready. | 6–8 km | 12–18 km/week |
How to choose a target time
Estimate a goal from a recent 10 km result and how well you handle long runs. For example, a 2:00 half marathon means about 5:41/km; check that the pace is sustainable in training, allowing for terrain and weather.
Common mistakes
- Increasing mileage abruptly: around 10% per week is only a reference; stop increasing when fatigue builds.
- Running every session fast: easy days need to stay easy.
- Skipping recovery weeks and rest, or scheduling hard sessions back to back.
- Trying gels and drinks for the first time on race day: practise fueling on long runs.
- Cramming in missed workouts and pushing through pain: reduce the load when pain appears instead of enduring it.
- Testing the full race distance just before the event and skipping the taper: use the final weeks to reduce fatigue.
How the AI coach adapts your plan
The AI coach uses available watch data: heart rate, HRV, sleep and completed training load. How you feel adds context to the numbers; unusual fatigue helps guide changes to upcoming sessions. After a missed workout, the plan is adjusted without squeezing everything into the remaining days. The timeline and target pace are refined as training progresses; outcomes depend on your starting fitness and consistency.
See how 1trAIner works
What you get during 7 days of free access
- First 7 days free: fill out the questionnaire about your running experience, your half marathon date, and your time for long runs.
- Get your first week's training plan, including a long session tailored to your current readiness.
- Review your training data and how you feel after the long run to refine the path to 21.1 km.
How it works
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1
You tell us about yourself
Share your level, how many days a week you can train, and your race date or target date. It takes five minutes in the chat or by filling out a questionnaire.
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2
You get a plan
The coach designs a training cycle leading up to your goal and lays out each week day by day: what to do, at what pace, and the purpose of each workout.
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3
The plan follows you
Workouts from your watch sync automatically, and you get feedback in the chat. Miss a session or get sick? Your weekly plan is adjusted.
Frequently asked questions
How do I train for a half marathon from scratch?
Start with run-walk sessions and three manageable workouts per week. Allow 16–20 weeks or more, establishing consistency before gradually building a long run toward 16–18 km when ready.
How many weeks do I need to prepare for a half marathon?
Allow around 16–20 weeks from scratch, or 10–12 with a base and comfortable 10 km runs. Extend the cycle if recovery slows; your ability to handle the load matters more than the calendar.
How do I choose a pace for a half marathon time goal?
Estimate a goal from a recent 10 km result and how well you handle long runs. For example, a 2:00 half marathon means about 5:41/km; check that the pace is sustainable in training, allowing for terrain and weather. Start with one quality session per week.
How much should I run each week before my first half marathon?
The example for regular runners builds from roughly 18–24 to 30–38 km per week, with a recovery week every 3–4 weeks. This is not a required minimum: starting mileage, time on feet and recovery matter more than the number.
Can I prepare for a half marathon in one month?
A month can cover the final preparation if you already run regularly and tolerate efforts close to the expected duration. From scratch, move the race date and follow a full cycle instead of compressing mileage increases.
Do I need to run 21 km before race day?
For a first finish, a long run of up to 16–18 km is often enough when you are ready for it. Keep it controlled: practise even pacing, drinking and fueling, and allow time to recover.
Do I need a sports watch?
No. You can start without one: the plan is based on your goal, level, and available time. With a Garmin or Apple Watch, the plan can be tailored more precisely — the coach can see your heart rate, sleep, and actual weekly training volume.
What happens after the free week?
The subscription costs 450 ₽ per month or 4999 ₽ per year. There are no automatic charges: your card details are not stored, and you renew manually using the link in the reminder.
Is the coach a person or a program?
1trAIner is an informational service: plans and reviews are prepared by AI based on your data. This is not a medical service and not a substitute for a doctor or an in-person coach.
What if my goal changes?
Let the coach know in the chat. Your plan is currently built around “Complete the half marathon distance (21.1 km) in 16 weeks of preparation”, but race dates can change, injuries happen, and vacations come up. The coach will adjust your training cycle to fit your new circumstances.
In the blog
The first 7 days are free, no card needed. No automatic charges: you renew your subscription manually.
Subscription terms are on the plans page and in the public offer. The service provides informational services and does not replace a doctor or an in-person coach.