What twelve weeks can reasonably change
The half marathon (13.1 miles) sits at a sweet spot: long enough to demand aerobic durability and disciplined pacing, short enough to train for without overwhelming your life, and fast enough to race at real intensity. It suits a 10K runner extending endurance, a marathoner sharpening threshold work, or a first-time half-marathoner with an established base.
Who this guide is for
This 12-week framework fits first-timers who can comfortably run 4-5 miles, intermediate runners targeting sub-2:00, sub-1:50, or sub-1:40, advanced runners chasing age-group PRs, and marathoners using the half as speed work. You should be running 15-20 miles per week comfortably before starting.
The three training phases
Phase 1: Base building (weeks 1-4, 20-30 miles/week): 3-4 easy runs (30-50 min), one tempo run (20-25 min at comfortably hard effort), one long run building from 8 to 11 miles. This builds the aerobic foundation that supports the faster work to come.
Sample week 2: Mon rest or easy 30 min, Tue tempo 25 min at half marathon effort, Wed easy 40 min, Thu easy 35 min, Fri rest or easy 30 min, Sat easy 45 min, Sun long run 10 miles easy.
Phase 2: Intensity development (weeks 5-9, 25-40 miles/week): 2-3 easy runs (40-60 min), one tempo or threshold session, one interval workout, one long run of 10-14 miles, some with race-pace segments. This builds speed endurance and teaches the body to sustain race pace.
Sample week 7: Mon rest, Tue 6 × 1 mile at 10K pace (2 min rest), Wed easy 45 min, Thu tempo 30 min at half marathon pace, Fri rest or easy 35 min, Sat easy 50 min, Sun long run 13 miles (6 miles at half marathon pace).
Phase 3: Peak and taper (weeks 10-12): Weeks 10-11 peak at 30-45 miles; week 12 drops 40-50% for taper.
Sample week 10 (peak): Mon rest, Tue 4 × 2 miles at half marathon pace (90 sec rest), Wed easy 50 min, Thu 8 × 800m at 5K-10K pace (90 sec rest), Fri easy 40 min, Sat easy 50 min, Sun long run 14 miles (final long run).
Sample week 12 (taper + race): Mon easy 30 min, Tue 6 × 400m at 5K pace (90 sec rest), Wed rest or easy 25 min, Thu easy 30 min with 4 × 20-sec strides, Fri rest, Sat shakeout 15 min + strides, Sun race day.
Essential workouts
Tempo runs: 20-40 minutes at comfortably hard pace (roughly half marathon to 10-mile pace) — 10 min easy warm-up, 25-35 min tempo, 10 min cool-down. You should be able to speak in short phrases but not hold a conversation. Improves the pace you can sustain before fatigue overwhelms you.
Race-pace long runs: Long runs with segments at goal pace, teaching the body to run fast while fatigued. Example: 12 miles total — 4 easy, 6 at half marathon pace, 2 easy. Don't start the race-pace segment too fast; build into it.
Intervals: Mile repeats (4-6 × 1 mile at 10K pace, 2 min rest), 1000m repeats (6-8 × 1000m at 10K pace, 90 sec rest), or 2-mile repeats (3-4 × 2 miles at half marathon pace, 2-3 min rest). Keep rest active rather than standing still.
Progression runs: Start easy, gradually increase pace, finish strong. Example: 10 miles — miles 1-4 easy, 5-8 moderate, 9-10 at half marathon effort.
The long run: Builds weekly from 8 to 14 miles, peaking 2-3 weeks before the race, and rehearses the effort and fueling decisions needed on race day. Variations include a standard easy effort, a progression finish, race-pace segments of 4-8 miles, or — for advanced runners — back-to-back moderate-long runs on consecutive days to simulate fatigue.
Pacing strategy
13.1 miles isn't a sprint, but it's fast enough to hurt if paced right. The ideal approach is even effort or a slight negative split: starting too fast means blowing up around mile 9-10; starting too conservatively leaves time on the table.
Run miles 1-3 at 5-10 seconds slower than goal pace — the first mile will feel ridiculously easy, so let the crowd thin out and resist the urge to surge. Hold goal pace through miles 4-10, monitoring effort rather than just pace since hills affect pace but not effort, and take nutrition as planned. Push from mile 10 onward, with everything left for the final mile and a sprint in the last 400m.
| Mile Range | Effort | Breathing | How It Feels |
|---|---|---|---|
| Miles 1-3 | 80-85% | Controlled | Could hold a short conversation |
| Miles 4-10 | 85-90% | Hard but rhythmic | Single word responses |
| Miles 11-13 | 90-100% | Labored to maximal | Focused solely on finish |
Fueling and hydration
Eat a carb-rich meal (300-500 calories) 2-3 hours before — bagel with peanut butter, oatmeal with banana, or toast with honey — plus an optional small snack (gel, banana, energy chews) 30-60 minutes out. Avoid high fiber, high fat, dairy, or new foods on race day.
Take small sips at aid stations (miles 3, 5, 7, 9, 11) without overhydrating. Runners finishing under 1:45 usually don't need fuel; over 1:45, take 1-2 gels around miles 6 and 10. Sports drinks can substitute for gels if you tolerate them well. Practice whatever plan you use during long runs first.
Afterward, get carbs and protein within 30 minutes, a full meal within 2 hours, and replace 16-24 oz of water per pound lost.
Common mistakes
Running every workout too hard, with no easy days — 80% of your miles should be conversational, with intensity saved for workouts. Skipping speed work and running only easy miles, instead of 1-2 quality tempo or interval sessions per week. Skipping rest days, when recovery is when the body actually adapts. Increasing mileage by more than 10% per week — build gradually and back off when symptoms or recovery say the progression isn't being absorbed. Never practicing goal race pace in training — work it into long runs and tempo sessions instead.
Race week
The night before: lay out your kit and fuel, eat a carb-rich dinner, hydrate through the day, and prioritize sleep two nights out more than race eve. Race morning: light carb breakfast, coffee if you normally drink it, steady water, arrive 60-75 minutes early. Warm up with 10-15 minutes of easy jogging, dynamic stretching, and 4-6 strides. After the gun: start 5-10 seconds slower than goal pace, settle into rhythm by mile 2-3, take water at every aid station, fuel as planned, and push hard from mile 11 to the finish.
Time goals and training paces
Use this table to determine training paces based on goal half marathon time:
| Goal Half | Per Mile Pace | Easy Pace | Tempo Pace | Interval Pace (10K) |
|---|---|---|---|---|
| 2:30:00 | 11:27 | 12:30-13:00 | 11:00-11:20 | 10:30-10:50 |
| 2:15:00 | 10:18 | 11:20-11:50 | 9:50-10:10 | 9:20-9:40 |
| 2:00:00 | 9:09 | 10:10-10:40 | 8:45-9:05 | 8:15-8:35 |
| 1:50:00 | 8:24 | 9:20-9:50 | 8:05-8:25 | 7:35-7:55 |
| 1:40:00 | 7:38 | 8:35-9:05 | 7:20-7:40 | 6:50-7:10 |
| 1:30:00 | 6:52 | 7:50-8:20 | 6:35-6:55 | 6:05-6:25 |
| 1:20:00 | 6:06 | 7:00-7:30 | 5:50-6:10 | 5:20-5:40 |
After your half marathon
Recovery: rest or easy cross-training in week 1, resume easy running at 50% normal volume in week 2, normal volume in week 3, quality workouts in week 4. Rule of thumb: one easy day for every mile raced, or 13 days of easy running or rest.
From there: race another half in 12-16 weeks to improve your time and work on weak areas, build toward a marathon with a 16-20 week block using this fitness as foundation, or drop to the 10K for speed with more interval work.
How kovaa helps half marathon runners
Training for a half marathon PR requires balancing easy mileage, tempo runs and intervals, long runs, and recovery. kovaa keeps the plan phase, weekly schedule, session structure, and intended effort together. Set the days you can train, review the relationship between faster sessions and the long run, and move work with adjacent load visible. Apple Health can add completed-activity context. The app does not guarantee a personal record or prevent injury.
Review the complete block
The half marathon rewards aerobic durability and pacing without the training volume a marathon demands, but it's still a demanding event that deserves real preparation and recovery — whether the goal is a first finish, a sub-2:00/1:50/1:40 breakthrough, or a controlled step toward a later marathon block. Recent training and race-day conditions ultimately determine whether the target pace is appropriate.
Review the half-marathon plan for the intended starting point, weekly demand, and phase structure.
Explore kovaa's half marathon training plan or read more training guides.
