Half marathon · Intermediate
1:45 half marathon plan: 12 weeks of training
A 12-week plan to run the half marathon in 1:45, an average of 4:59/km. Level: intermediate, 4 sessions a week.
- Duration
- 12 weeks
- Sessions / week
- 4
- Peak volume
- 47 km
- Longest run
- 20 km
- Target pace
- 4:59/km
The half marathon demands as much endurance as speed. These plans first build a solid aerobic base, then bring in threshold and race-pace work, before a taper that gets you to the start line fresh.
The long run grows week after week: it is what lets you hold your pace over the final kilometres.
Weekly volume
Plan phases
Base phase: aerobic foundations. Respect your HR zones and the progression — consistency beats intensity.
Build phase: quality workouts come in. The 48 h of recovery after each hard workout are non-negotiable.
Peak phase: volume and intensity at their highest. Look after your sleep and nutrition — this is where months of training come together.
Taper: volume gradually drops so you arrive fresh on race day. Resist the urge to do more — fatigue fades, form rises.
The plan week by week
Week 1Base33 km
Base phase: aerobic foundations. Respect your HR zones and the progression — consistency beats intensity.
Easy run50 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 50 min.
Easy run50 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 50 min.
Easy run50 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 50 min.
Long run9.2 km · Zone 2
Long run (zone 2). The fundamental workout for building your aerobic base. Keep a conversational effort throughout — if you can no longer talk, slow down. Drink regularly every 20–25 min. Target pace: 5'49"–6'19"/km. Target distance: 9.2 km.
Week 2Base36 km
Base phase: aerobic foundations. Respect your HR zones and the progression — consistency beats intensity.
Easy run55 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 55 min.
Easy run55 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 55 min.
Easy run55 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 55 min.
Long run10.1 km · Zone 2
Long run (zone 2). The fundamental workout for building your aerobic base. Keep a conversational effort throughout — if you can no longer talk, slow down. Drink regularly every 20–25 min. Target pace: 5'49"–6'19"/km. Target distance: 10.1 km.
Week 3Base40 km
Base phase: aerobic foundations. Respect your HR zones and the progression — consistency beats intensity.
Easy run60 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 60 min.
Easy run60 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 60 min.
Easy run60 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 60 min.
Long run11.1 km · Zone 2
Long run (zone 2). The fundamental workout for building your aerobic base. Keep a conversational effort throughout — if you can no longer talk, slow down. Drink regularly every 20–25 min. Target pace: 5'49"–6'19"/km. Target distance: 11.1 km.
Week 4BaseRecovery29 km
Recovery week (volume –25%): locking in the adaptations. Don't compensate by running faster — recovery is training in its own right.
Easy run50 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 50 min.
Recovery35 min · Zone 1
Active recovery (zone 1). Very easy jog at whatever pace feels natural. Fully relaxed muscles, no performance pressure — if you feel very tired, walk instead. Target pace: 6'39"–7'09"/km. Target duration: 35 min.
Easy run50 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 50 min.
Long run8.3 km · Zone 2
Long run (zone 2). The fundamental workout for building your aerobic base. Keep a conversational effort throughout — if you can no longer talk, slow down. Drink regularly every 20–25 min. Target pace: 5'49"–6'19"/km. Target distance: 8.3 km.
Week 5Base43 km
Base phase: aerobic foundations. Respect your HR zones and the progression — consistency beats intensity.
Easy run65 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 65 min.
Easy run65 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 65 min.
Easy run65 min · Zone 2
Base endurance (zone 2). Easy running at a conversational pace — you should be able to speak in full sentences without getting out of breath. The backbone of the base phase: resist the urge to go faster. Target pace: 6'04"–6'34"/km. Target duration: 65 min.
Long run12.2 km · Zone 2
Long run (zone 2). The fundamental workout for building your aerobic base. Keep a conversational effort throughout — if you can no longer talk, slow down. Drink regularly every 20–25 min. Target pace: 5'49"–6'19"/km. Target distance: 12.2 km.
Week 6Build44 km
Build phase: quality workouts come in. The 48 h of recovery after each hard workout are non-negotiable.
Easy run80 min · Zone 2
Base endurance (zone 2). A supporting run between quality workouts. Keep a strictly conversational pace to aid recovery and save your energy for the hard sessions. Target pace: 6'04"–6'34"/km. Target duration: 80 min.
Recovery45 min · Zone 1
Active recovery (zone 1). Very easy jog. An essential role between quality workouts: clearing metabolic waste and preparing for the next load. Target pace: 6'39"–7'09"/km. Target duration: 45 min.
Tempo / threshold60 min · Zone 4
Lactate threshold (zone 3–4). Sustained effort, slightly uncomfortable but under control. Suggested structure: 1 × 25 min or 2 × 15 min (3 min recovery). This is the workout that pushes your lactate threshold up. Target pace: 5'09"–5'29"/km. Target duration: 60 min. Target HR zone: 4.
Long run14.4 km · Zone 2
Progressive long run (zone 2, last km in zone 3). Start easy and run the final 20–30% slightly faster (zone 3). Goal: simulate late-race fatigue and practise your race rhythm. Target pace: 5'49"–6'19"/km. Target distance: 14.4 km.
Week 7Build45 km
Build phase: quality workouts come in. The 48 h of recovery after each hard workout are non-negotiable.
Easy run80 min · Zone 2
Base endurance (zone 2). A supporting run between quality workouts. Keep a strictly conversational pace to aid recovery and save your energy for the hard sessions. Target pace: 6'04"–6'34"/km. Target duration: 80 min.
Recovery45 min · Zone 1
Active recovery (zone 1). Very easy jog. An essential role between quality workouts: clearing metabolic waste and preparing for the next load. Target pace: 6'39"–7'09"/km. Target duration: 45 min.
Tempo / threshold60 min · Zone 4
Lactate threshold (zone 3–4). Sustained effort, slightly uncomfortable but under control. Suggested structure: 1 × 25 min or 2 × 15 min (3 min recovery). This is the workout that pushes your lactate threshold up. Target pace: 5'09"–5'29"/km. Target duration: 60 min. Target HR zone: 4.
Long run15.8 km · Zone 2
Progressive long run (zone 2, last km in zone 3). Start easy and run the final 20–30% slightly faster (zone 3). Goal: simulate late-race fatigue and practise your race rhythm. Target pace: 5'49"–6'19"/km. Target distance: 15.8 km.
Week 8BuildRecovery39 km
Recovery week (volume –25%): locking in the adaptations. Don't compensate by running faster — recovery is training in its own right.
Easy run65 min · Zone 2
Base endurance (zone 2). A supporting run between quality workouts. Keep a strictly conversational pace to aid recovery and save your energy for the hard sessions. Target pace: 6'04"–6'34"/km. Target duration: 65 min.
Recovery45 min · Zone 1
Active recovery (zone 1). Very easy jog. An essential role between quality workouts: clearing metabolic waste and preparing for the next load. Target pace: 6'39"–7'09"/km. Target duration: 45 min.
Easy run65 min · Zone 2
Base endurance (zone 2). A supporting run between quality workouts. Keep a strictly conversational pace to aid recovery and save your energy for the hard sessions. Target pace: 6'04"–6'34"/km. Target duration: 65 min.
Long run11.9 km · Zone 2
Progressive long run (zone 2, last km in zone 3). Start easy and run the final 20–30% slightly faster (zone 3). Goal: simulate late-race fatigue and practise your race rhythm. Target pace: 5'49"–6'19"/km. Target distance: 11.9 km.
Week 9Build47 km
Build phase: quality workouts come in. The 48 h of recovery after each hard workout are non-negotiable.
Easy run80 min · Zone 2
Base endurance (zone 2). A supporting run between quality workouts. Keep a strictly conversational pace to aid recovery and save your energy for the hard sessions. Target pace: 6'04"–6'34"/km. Target duration: 80 min.
Recovery45 min · Zone 1
Active recovery (zone 1). Very easy jog. An essential role between quality workouts: clearing metabolic waste and preparing for the next load. Target pace: 6'39"–7'09"/km. Target duration: 45 min.
Tempo / threshold60 min · Zone 4
Lactate threshold (zone 3–4). Sustained effort, slightly uncomfortable but under control. Suggested structure: 1 × 25 min or 2 × 15 min (3 min recovery). This is the workout that pushes your lactate threshold up. Target pace: 5'09"–5'29"/km. Target duration: 60 min. Target HR zone: 4.
Long run17.4 km · Zone 2
Progressive long run (zone 2, last km in zone 3). Start easy and run the final 20–30% slightly faster (zone 3). Goal: simulate late-race fatigue and practise your race rhythm. Target pace: 5'49"–6'19"/km. Target distance: 17.4 km.
Week 10Peak47 km
Peak phase: volume and intensity at their highest. Look after your sleep and nutrition — this is where months of training come together.
Intervals60 min · Zone 5
VO₂max intervals — sharpening (zone 4–5). Race-specific speed work. Structure: 8 × 3 min or 5 × 5 min, 90 s recovery. The last speed block before the taper — aim for quality on every rep. Target pace: 4'34"–4'54"/km. Target duration: 60 min. Target HR zone: 5.
Recovery45 min · Zone 1
Active recovery (zone 1). A short, very easy jog. In the peak phase, quality recovery matters as much as quality workouts — don't try to do more. Target pace: 6'39"–7'09"/km. Target duration: 45 min.
Tempo / threshold65 min · Zone 4
Lactate threshold — maximum intensity (zone 4). Effort close to race pace, hard but manageable. Structure: 2 × 20 min or 1 × 35 min. Focus on even pacing: the tempo should stay steady to the end. Target pace: 5'09"–5'29"/km. Target duration: 65 min.
Long run19.6 km · Zone 3
Long run with race-pace blocks (zone 2–3). Include 2–3 blocks of 5–8 km at target race pace in the middle of the run. Rehearse race conditions: fuelling, kit, effort management. Target pace: 5'49"–6'19"/km. Target distance: 19.6 km. Target HR zone: 3.
Week 11Peak47 km
Peak phase: volume and intensity at their highest. Look after your sleep and nutrition — this is where months of training come together.
Intervals60 min · Zone 5
VO₂max intervals — sharpening (zone 4–5). Race-specific speed work. Structure: 8 × 3 min or 5 × 5 min, 90 s recovery. The last speed block before the taper — aim for quality on every rep. Target pace: 4'34"–4'54"/km. Target duration: 60 min. Target HR zone: 5.
Recovery45 min · Zone 1
Active recovery (zone 1). A short, very easy jog. In the peak phase, quality recovery matters as much as quality workouts — don't try to do more. Target pace: 6'39"–7'09"/km. Target duration: 45 min.
Tempo / threshold65 min · Zone 4
Lactate threshold — maximum intensity (zone 4). Effort close to race pace, hard but manageable. Structure: 2 × 20 min or 1 × 35 min. Focus on even pacing: the tempo should stay steady to the end. Target pace: 5'09"–5'29"/km. Target duration: 65 min.
Long run19.6 km · Zone 3
Long run with race-pace blocks (zone 2–3). Include 2–3 blocks of 5–8 km at target race pace in the middle of the run. Rehearse race conditions: fuelling, kit, effort management. Target pace: 5'49"–6'19"/km. Target distance: 19.6 km. Target HR zone: 3.
Week 12Taper36 km
Taper: volume gradually drops so you arrive fresh on race day. Resist the urge to do more — fatigue fades, form rises.
Easy run35 min · Zone 2
Light run (zone 1–2). A very easy pace to keep the legs ticking over without adding fatigue. A good chance to work on form and relaxation. Target pace: 6'04"–6'34"/km. Target duration: 35 min. Target HR zone: 2.
Recovery25 min · Zone 1
Active recovery (zone 1). Light jog to keep the blood flowing. Don't push: the taper is there so you arrive fresh on the start line. Target pace: 6'39"–7'09"/km. Target duration: 25 min.
Easy run35 min · Zone 2
Light run (zone 1–2). A very easy pace to keep the legs ticking over without adding fatigue. A good chance to work on form and relaxation. Target pace: 6'04"–6'34"/km. Target duration: 35 min. Target HR zone: 2.
Race21.1 km · Zone 4
Race day — Road race 21.1 km. All your training leads to this moment. Start at your target pace, stay patient in the first kilometres and trust your training. Target pace: 4'59''/km. Target HR zone: 4. Enjoy every moment.
Plan generated by the Paceo algorithmic engine. This plan is a planning aid and is not a substitute for advice from a health professional or a qualified coach. If you have persistent pain, see a doctor before resuming training.
This plan is a starting point.
On Paceo, it fits your real race date, your VO2max pace and the workouts imported from your Garmin, Coros, Suunto or Strava, then adjusts every week with Kairn, your AI coach.
Tailor this planFrequently asked questions
How many weeks to train for a half marathon?
10 to 12 weeks for a regular runner. A first half is best tackled after a few months of running and a 10K already under your belt.
How long should the longest run be before a half marathon?
It builds gradually: around 17 km for a first half, up to 20–22 km if you are chasing a time. Running the full distance in training is not essential, but going slightly beyond it at an easy pace builds endurance.
What pace for a 1:45 half marathon?
4:59 per kilometre, just over 12 km/h. Start slightly slower over the first kilometres.