12 Week Half Marathon Training Plan
This 12-week half marathon training plan has four runs a week: two easy runs, one quality session and a long run that builds from 10 km to 19 km (11.8 mi) in week 10. Every fourth week is a lighter cutback week, and the last two weeks, race week included, are the taper. The full dated plan below is a sample for a 2:00:00 goal and a race on Sunday 18 April 2027.
Twelve weeks is the standard half marathon block. It suits a runner who already runs three or four times a week and can manage an easy hour.
12weeks
- Day one
- Monday 25 January 2027
- Race day
- Sunday 18 April 2027
- Runs a week
- 4
- Peak long run
- 19 km
- 11.8 mi
- Peak week
- 46.5 km
- 28.9 mi
- Goal pace
- 9:09/mi
- 5:41/km
What does the 12-week plan look like, week by week?
Sample: Half marathon goal 2:00:00, 4 days a week, race day Sunday 18 April 2027. Day one is Monday 25 January 2027. Base weeks 1-4, Build weeks 5-10, Taper week 11, race week is week 12. Distances are in km with miles alongside; each weekly total includes warm-ups and cool-downs, and race week includes the race itself.
- EEasy
- SEasy + strides
- TThreshold
- IIntervals
- LLong run
- RRace
- Cutback lighter week
| Week | Mon | Wed | Fri | Sun | Total |
|---|---|---|---|---|---|
| Base · weeks 1-4 | |||||
| 1Week 125 Jan - 31 Jan | Mon 25 JanEEasy 6 km | Wed 27 JanSEasy 6 km + strides | Fri 29 JanEEasy 6 km | Sun 31 JanLLong run 10 km 6.2 mi | 28 km17.4 mi |
| 2Week 21 Feb - 7 Feb | Mon 1 FebEEasy 6 km | Wed 3 FebSEasy 6 km + strides | Fri 5 FebEEasy 6 km | Sun 7 FebLLong run 11 km 6.8 mi | 29 km18.0 mi |
| 3Week 38 Feb - 14 Feb | Mon 8 FebEEasy 6 km | Wed 10 FebSEasy 6 km + strides | Fri 12 FebEEasy 6 km | Sun 14 FebLLong run 12 km 7.5 mi | 30 km18.6 mi |
| 4Week 415 Feb - 21 FebCutback | Mon 15 FebEEasy 6 km | Wed 17 FebSEasy 6 km + strides | Fri 19 FebEEasy 6 km | Sun 21 FebLLong run 10 km 6.2 mi | 28 km17.4 mi |
| Build · weeks 5-10 | |||||
| 5Week 522 Feb - 28 Feb | Mon 22 FebEEasy 7 km | Wed 24 FebT3 × 6 min threshold | Fri 26 FebEEasy 7 km | Sun 28 FebLLong run 14 km 8.7 mi | 35.5 km22.1 mi |
| 6Week 61 Mar - 7 Mar | Mon 1 MarEEasy 7 km | Wed 3 MarI6 × 800 m intervals | Fri 5 MarEEasy 7 km | Sun 7 MarLLong run 15 km 9.3 mi | 40.5 km25.2 mi |
| 7Week 78 Mar - 14 Mar | Mon 8 MarEEasy 7 km | Wed 10 MarT4 × 8 min threshold | Fri 12 MarEEasy 7 km | Sun 14 MarLLong run 16 km 9.9 mi | 40.5 km25.2 mi |
| 8Week 815 Mar - 21 MarCutback | Mon 15 MarEEasy 6 km | Wed 17 MarI5 × 800 m intervals | Fri 19 MarEEasy 6 km | Sun 21 MarLLong run 14 km 8.7 mi | 36.5 km22.7 mi |
| 9Week 922 Mar - 28 Mar | Mon 22 MarEEasy 7 km | Wed 24 MarT4 × 10 min threshold | Fri 26 MarEEasy 7 km | Sun 28 MarLLong run 18 km 11.2 mi | 44 km27.3 mi |
| 10Week 1029 Mar - 4 Apr | Mon 29 MarEEasy 7 km | Wed 31 MarI5 × 1200 m intervals | Fri 2 AprEEasy 7 km | Sun 4 AprLLong run 19 km 11.8 mi | 46.5 km28.9 mi |
| Taper · week 11 | |||||
| 11Week 115 Apr - 11 Apr | Mon 5 AprEEasy 5 km | Wed 7 AprT3 × 6 min threshold | Fri 9 AprEEasy 5 km | Sun 11 AprLLong run 13 km 8.1 mi | 30.5 km19.0 mi |
| Race week · week 12 | |||||
| 12Week 1212 Apr - 18 Apr | Mon 12 AprEEasy 4 km | Wed 14 AprTRace-week sharpener2 × 5 min at threshold, full recovery. Short and crisp. | Fri 16 AprEEasy 4 km | Sun 18 AprRRace day: Half marathon | 35 km21.7 mi |
What pace should each run in the plan be?
The paces come from your VDOT, the fitness score a race time implies in Jack Daniels' tables. A 2:00:00 half marathon works out at a VDOT of 36.5, which puts easy running at 10:08-11:38 per mile (6:18-7:14 per km). Easy really does mean easy: most of the plan is run at that pace.
| Run type | Per mile | Per km |
|---|---|---|
| Easy and longMost of your running. Conversational, builds the aerobic base. | 10:08-11:38 | 6:18-7:14 |
| ThresholdComfortably hard, about one hour race effort. Raises the pace you can hold. | 8:50 | 5:29 |
| IntervalHard 3 to 5 minute reps. Builds VO2 max. | 8:08 | 5:03 |
| Goal race pace2:00:00 over half marathon distance. | 9:09 | 5:41 |
Source: Jack Daniels, Daniels' Running Formula (Human Kinetics), VDOT tables. How we compute them is on the methodology page.
How is this half marathon training plan built?
The plan is counted back from race day, so week 12 ends on the race and week 1 starts 83 days earlier. It runs in four phases:
- Base, weeks 1-4. Easy running and strides only. The long run goes 10 to 12 km, and weeks total 28 to 30 km.
- Build, weeks 5-10. Quality sessions (threshold and intervals) join the easy running. The long run goes 14 to 19 km, and weeks total 35.5 to 46.5 km.
- Taper, week 11. Volume comes down but the quality session stays, kept short. The long run is 13 km.
- Race week, week 12. A short sharpener midweek, easy shakeouts, then the race on Sunday 18 April 2027.
Cutback weeks. Every fourth week is lighter so the training can sink in: week 4 (long run 10 km after 12 km) and week 8 (long run 14 km after 16 km). The last build week, week 10, is never a cutback.
Taper. The taper lasts two weeks including race week. Against the 46.5 km peak week, week 11 totals 30.5 km (66%), and race week has 13.9 km of running before the race. A meta-analysis of taper studies found the best results from a taper of 8 to 14 days that cut volume by 41 to 60% while keeping intensity, which is why the quality session stays in.
Source: Bosquet L, Montpetit J, Arvisais D, Mujika I. Effects of tapering on performance: a meta-analysis. Medicine & Science in Sports & Exercise 39(8), 2007.
What does each run type in the plan mean?
Each run in the table carries a letter. 39 of the plan's 48 runs (81%) are easy runs, strides or long runs, which together cover 76% of its 424 km. Studies of endurance athletes find the same pattern: around 80% of training sessions are done at low intensity, with the hard work kept to the rest.
- E
Easy 24 runs · 10:08-11:38/mi · 6:18-7:14/km
Conversational running. It builds the aerobic base and lets you recover from the hard days.
First one: week 1, Easy 6 km. Conversational pace.
- S
Easy + strides 4 runs · 10:08-11:38/mi · 6:18-7:14/km
An easy run with a few short, relaxed accelerations at the end. Strides keep some leg speed during the base weeks without adding fatigue.
First one: week 1, Easy 6 km + strides. Easy run, then 6 × 20 s relaxed fast strides with a walk back.
- T
Threshold 5 runs · 8:50/mi · 5:29/km
Comfortably hard reps, about the effort you could hold for an hour in a race. They raise the pace you can sustain before fatigue builds quickly.
First one: week 5, 3 × 6 min threshold. 3 × 6 min at threshold pace, 1 min jog between.
- I
Intervals 3 runs · 8:08/mi · 5:03/km
Hard reps of about 3 to 5 minutes with equal jog recovery. They work on your VO2 max, the top of your aerobic range.
First one: week 6, 6 × 800 m intervals. 6 × 800 m at interval pace, equal-time jog between.
- L
Long run 11 runs · 10:08-11:38/mi · 6:18-7:14/km
The longest run of the week, at easy pace. It builds endurance and is the place to rehearse race-day fuel.
First one: week 1, Long run 10 km. Easy pace the whole way. Practise race-day fuel on the longer ones.
- R
Race 1 run
Race day. Start at goal pace, not faster, and let the pace band keep you honest.
First one: week 12, Race day: Half marathon. Start at goal pace, not faster. Use the pace band.
Source: Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance 5(3), 2010.
How do you adjust the plan for 3, 5 or 6 days a week?
The long run and the phases stay the same; what changes is how many easy runs and quality sessions sit around them. On three days the plan runs Tue, Thu and Sun and keeps one quality session, peaking at 39.5 km (24.5 mi) a week. On six days it runs Mon, Tue, Wed, Thu, Fri and Sun, with threshold and intervals in a peak week, and tops out at 63 km (39.1 mi). Add days only when the current number feels easy; the extra runs are easy running, not extra hard sessions.
| Days | Quality sessions | Peak week | Peak long run | Whole plan |
|---|---|---|---|---|
| 3 days | 1 a week: Threshold or Intervals | 39.5 km / 24.5 mi | 19 km / 11.8 mi | 350 km |
| 4 days | 1 a week: Threshold or Intervals | 46.5 km / 28.9 mi | 19 km / 11.8 mi | 424 km |
| 5 days | 2 a week: Threshold + Intervals | 56 km / 34.8 mi | 19 km / 11.8 mi | 524 km |
| 6 days | 2 a week: Threshold + Intervals | 63 km / 39.1 mi | 19 km / 11.8 mi | 598 km |
When should you start a 12-week half marathon plan?
Count back from race day. The plan ends on the race, so day one is 12 weeks minus one day before it. For a race on Sunday 18 April 2027:
12 weeks × 7 days = 84 days, ending on race day
Sunday 18 April 2027 minus 83 days
Start on Monday 25 January 2027
The planner offers 8, 12 and 16 weeks for a half marathon and picks the longest that fits before your race. These are the start dates for the same race day:
| Plan length | Start | Taper |
|---|---|---|
| 8 weeks | Monday 22 February 2027 | 2 weeks |
| 12 weeks | Monday 25 January 2027 | 2 weeks |
| 16 weeks | Monday 28 December 2026 | 2 weeks |
The planner builds this same plan for your own goal time or a recent race result, counted back from your race date, with your training paces, race-day splits, a pace band and a calendar file.
Open the planner: Half 2:00:00Frequently asked questions
How many weeks do you need to train for a half marathon?
The planner builds half marathon plans from 8 to 16 weeks and picks the longest one that fits before your race. This page shows the 12-week version. If you already run regularly, the shorter end works; if you are newer to running or coming back from a break, give yourself the full 16 weeks.
How long is the longest run in this half marathon plan?
19 km (11.8 mi), in week 10, which is two weeks before race day. The long run starts at 10 km and is always run at easy pace.
How many days a week do I need to run?
Three to six. This sample uses 4. On three days the peak week is 39.5 km (24.5 mi); the long run is the same whatever you choose. Pick the number you can keep up every week, not the most you can manage once.
What should I do if I miss a week?
Pick the plan up at the current week rather than trying to make the missed runs up. If you miss more than a week, rebuild the plan in the planner from today's date: it counts back from race day again and chooses a length that still fits.
Can I print the plan or put it in my calendar?
Yes. The print button lays this table out on Letter or A4 without the site's menus. The planner builds the same plan for your own goal and race date and exports it as a calendar file for Google, Apple or Outlook, plus a printable PDF. No email or account is needed.
Where do the training paces come from?
From the goal time, through Jack Daniels' VDOT formula. A 2:00:00 half marathon gives a VDOT of 36.5. If you have a recent race result, enter that in the planner instead: paces based on current fitness are safer than paces based on a hope.