Quick summary
- Who it's for: runners who have finished a half marathon and currently run 25–35 km a week, three to five days a week.
- The plan: 14 weeks, peaking at about 52 km a week with a 30 km (or 3-hour) long run.
- The big change: the marathon isn't a longer half. Pacing and fueling matter far more after 30 km.
- Pace rule: most running is easy; goal-pace work starts in week 6.
- First-marathon goal: finish strong and in control. Chase a time at your second marathon.
You've run a half marathon. Now you want the full distance. The good news: the fitness you've built is a strong base. The challenge: the marathon is not simply twice as far. After about 30 km your body runs low on stored carbohydrate, your legs meet fatigue they've never felt, and small pacing mistakes from the first hour come back with interest.
This 14-week plan bridges that gap, with a gradual build in long runs, some goal-pace practice and a proper taper.
Are you ready to step up?
You're ready to start this plan if you can tick most of these:
- You've finished a half marathon in the last 6–12 months, or can comfortably run 16 km.
- You currently run 25–35 km a week, on three to five days.
- You've had no injury that stopped you running in the last two months.
- You can commit to four or five runs a week for 14 weeks, including one long run.
If you're below this, spend 4–6 weeks building easy mileage first.
Setting your marathon goal
For a first marathon, a sensible goal is to finish feeling in control. If you want a number, a common rough guide is that a marathon takes a little more than double your recent half-marathon time:
| Recent half marathon | First-marathon target range |
|---|---|
| 1:40 | 3:35–3:50 |
| 1:50 | 3:55–4:10 |
| 2:00 | 4:15–4:30 |
| 2:15 | 4:45–5:00 |
| 2:30 | 5:15–5:35 |
These ranges are deliberately cautious for a first marathon. Once you have a target, find your marathon pace in our marathon pace chart.
Your training paces
- Easy: conversational. Most of your running. Roughly 60–90 seconds per km slower than marathon pace.
- Long run: comfortable, 45–90 seconds per km slower than marathon pace. See long-run pace by goal time.
- Marathon pace (MP): your goal race pace. Controlled; you can speak in short sentences.
- Threshold: comfortably hard, about your 10-mile to half-marathon race effort.
- Faster repeats: around 10K race effort.
The 14-week plan
Each week has three key runs. Fill the other one or two days with easy running.
| Week | Weekly km | Midweek session | Marathon-pace work | Long run |
|---|---|---|---|---|
| 1 | 32 | 4 × 1 km threshold, 2 min jog | — | 14 km easy |
| 2 | 35 | 20 min steady at threshold | — | 16 km |
| 3 | 38 | 6 × 3 min at 10K effort, 2 min jog | — | 18 km |
| 4 | 32 | Easy + 6 × 20 s strides | — | 14 km (recovery week) |
| 5 | 40 | 3 × 10 min threshold | — | 20 km |
| 6 | 43 | 6 × 3 min at 10K effort | 5 km MP within a 10 km run | 22 km |
| 7 | 46 | 2 × 15 min threshold | Last 4 km of long run at MP | 24 km |
| 8 | 38 | Half-marathon race or 15 km steady | — | The race is the long run (recovery week) |
| 9 | 48 | 5 × 1 km at 10K effort | 8 km MP within a 13 km run | 26 km |
| 10 | 50 | 3 × 2 km threshold | Last 6 km of long run at MP | 28 km |
| 11 | 52 | 2 × 15 min threshold | 10 km MP within a 15 km run | 30 km or 3 hours, whichever comes first |
| 12 | 44 | 4 × 1 km at 10K effort | 6 km MP | 22 km |
| 13 | 34 | 6 × 400 m relaxed + strides | 3 × 2 km MP | 16 km |
| 14 | 18 + race | 3 × 1 km MP on Tuesday | Race day | Marathon |
Weeks 12–14 are your taper. If you want to understand why the volume drops, read how to taper for a marathon.
What changes from half to full
Fueling becomes essential
In a half marathon, many runners can get by on stored carbohydrate. In a marathon you can't. Plan to take 60–90 g of carbohydrate per hour from about 30–40 minutes in, and practise it on every long run from week 5. Our marathon fueling plan gives the exact numbers for your finish time.
Pacing becomes unforgiving
Running 10 seconds per km too fast for the first 20 km of a half might cost you a minute at the end. In a marathon it can cost 10–20 minutes, because it burns through your carbohydrate stores early. Start the race 5–10 seconds per km slower than goal pace and settle in after 10 km.
Recovery takes longer
Long runs of 24 km and over take more out of you than anything in half-marathon training. Keep the day after easy or rest, and protect your sleep.
Your kit gets tested harder
Chafing, blisters and gut problems that never appeared over 21 km often show up after 30 km. Test everything you'll wear and eat on your 26 km and 30 km long runs. See our marathon race-day kit checklist.
Race-day strategy for your first marathon
- Start slow. The first 5 km should feel too easy.
- Halfway is a checkpoint, not a target. You should feel like you've barely started.
- Fuel on schedule, not when you feel tired. By then it's late.
- Walk the aid stations if you need to. Ten seconds of walking to drink properly costs less than a missed drink.
- Hold back until 32 km. If you still feel good, the last 10 km is where you can push.
FAQ
How long does it take to go from a half marathon to a marathon?
For most runners who have recently finished a half marathon and run 25–35 km a week, 14–18 weeks is enough to prepare for a first marathon. Runners with a lower base should add a few weeks of easy running first.
How many kilometres a week do I need for a first marathon?
Most first-time marathoners peak at around 45–60 km (28–37 miles) a week. This plan peaks at 52 km, which is enough to finish strongly for most runners.
What is a good first marathon time?
There's no single good time. A first marathon in the 4:00–5:00 range is common for recreational runners. Finishing strong and uninjured is a better first goal than a specific time.
Do I need to run 32 km before my first marathon?
No. A peak long run of 28–32 km, or about 3 hours, is enough. Race-day adrenaline, the taper and good fueling cover the remaining distance.
Can I walk during a marathon?
Yes. Planned short walk breaks, such as walking through aid stations, are a legitimate strategy and can help you finish faster than slowing down sharply later.
This article is general training information, not medical advice. Check with a doctor before starting a new training programme, especially if you have a health condition.