Half Marathon
21 kilometers don't happen by accident
The coach that runs with you
Your first half — or your next PR — needs a plan that builds endurance week by week and tells you exactly what pace to run.
Free during beta · Strava · Garmin
You can run 15km no problem. But from 15 to 21, the same thing always happens: your pace falls apart.
The half marathon is a deceptive distance. It seems accessible — 'just' 21km — but it requires a precise balance of volume, threshold, and specific pace that most generic plans don't address.
Your plan inside
This is a half marathon plan with PRB
Progressive long runs
From 14km to 18-20km. The last ones with segments at half marathon pace so your body learns to sustain that pace under accumulated fatigue.
Max long run: 18-20km. Progressive, not linear.
Calibrated race pace
Your half marathon pace lives between Tempo and Marathon zones. PRB calculates exactly where using your VDOT. You train it in specific sessions so race day is no surprise.
1 specific pace session per week.
Aerobic base + threshold
Easy volume to build endurance + tempo to push your threshold up. The balance between both is what makes the difference in half marathon.
55-80km weekly depending on level.
Continuous adaptation
12-16 weeks is a long time. Life will get in the way. Your plan absorbs bad weeks without destroying the progression.
Automatic weekly recalibration based on Strava data.
What happened
What's next
Sample week
Week 10 of 14 — Specific phase
VDOT 48 · 61km total · 2 quality sessions + long run at specific pace
The science behind it
The methodologies behind your half marathon plan
PRB selects the optimal pattern for your level, volume, and goal.
Pete Pfitzinger
Half and full marathon plans with phase-based periodization. The reference for 50-120km/week runners.
PeriodizationJack Daniels
VDOT tables for pace zones. The world standard in intensity prescription.
Pace zonesIs it for you?
This plan is for you if...
Your first half marathon
You want to break 1h45
You want to break 1h30
You're coming from 10K and want to level up
You've run a half but always fade after km 15
Frequently asked questions about your half marathon plan
Not necessarily. Long runs of 18-20km are enough. The key is the quality of those kilometers, not reaching 21km in training.
It depends on your current VDOT. PRB gives you a prediction based on real data, not hopes. Half marathon pace sits between your Tempo and Marathon zones.
2-3, depending on your total volume and level. PRB balances quality and recovery so you don't overload.
Depends on your current base. 12-16 weeks is ideal. PRB evaluates viability based on your volume and level.
More volume, more long runs, and the introduction of specific half marathon pace as a key session. The 10K lives at threshold; the half sits between threshold and marathon pace.
Your next half marathon deserves a plan that won't leave you alone at km 17.
Tell me your date, your goal, and what you run today. I'll build you a half marathon plan with progressive long runs, calibrated pace, and real adaptation.
Your half marathon prediction
VDOT 48.2 → 1:32:40
Target pace: 4:23/km
10km split: 43:50
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