What Pace Should My Long Run Be? (By Goal Marathon)

Here is the quick answer. Run most of your long run easy — about 30 to 40 seconds per kilometer slower than your goal marathon pace. Later in your training, add some segments at marathon pace. The table below shows both, by goal time.

Find your goal marathon, then read across for your easy pace and your marathon-pace (MP) segment pace.

Goal marathon	Easy long-run /km	MP segments /km
3:00	4:44	4:16
3:30	5:29	4:59
4:00	6:14	5:41
4:30	6:59	6:24
5:00	7:45	7:07

The quick answer

Your long run has two speeds.

Easy pace is for most of the run. It should feel relaxed. You can talk in full sentences. This is about 30 to 40 seconds per kilometer slower than your goal marathon pace. Going even slower is fine (RunnersConnect, 2024).

Marathon-pace (MP) segments are faster. They match the pace you want on race day. You add these inside some long runs, later in your training.

Why mostly easy? Because the long run is built to grow your endurance, not to wear you out. A big study of marathon and half-marathon runners found that a longer long run and more weekly miles go with faster race times (Fokkema et al., 2020). The goal is to finish strong and recover fast — so you can do it again next week.

Why most runners run long runs too fast

This is the most common long-run mistake. It feels good to push. But it costs you.

When you run the long run too fast, three things happen:

1. You get too tired to train well the rest of the week. A hard long run needs days of recovery. That steals your easy miles and your workouts.
2. You raise your injury risk. Tired legs over many kilometers break down. Slower miles are safer miles.
3. You miss the point. The long run builds your aerobic base — your heart, your blood vessels, and your fat-burning. Easy running does that best.

Coaches often say to run long runs one to two minutes per mile slower than marathon pace (McMillan Running). If you can chat the whole way, you are doing it right. If you are breathing hard, slow down.

When to add marathon-pace segments

Early in training, keep long runs all easy. Build the distance first.

As race day gets closer — about the last 8 to 10 weeks — start adding marathon-pace segments inside some long runs. A simple version is the fast-finish long run: run easy, then pick up to goal marathon pace for the last 30 to 60 minutes (McMillan Running).

This does two jobs. It teaches your legs the race rhythm. And it trains you to run fast when you are already tired — exactly what the last few miles of a marathon feel like.

Keep the MP segments controlled. They should feel like your race, not faster. Use the MP column in the table above as your target.

Find your paces

Enter a recent race and let PIRX project your marathon time — free, no signup, no watch. You will see your goal marathon pace and the easy pace to train at.

PIRX's proprietary machine-learning prediction engine learns your style instead of using one fixed formula. It shows a supported range for your marathon, not a fake-exact number, so your training paces sit on real fitness — not a guess.

This is what makes PIRX different. Strava tells you what you did. Garmin shows your data. PIRX tells you why it happened and what's next — with validated prediction accuracy of 98% across PIRX users.

New here? Start with the complete guide to predicting your race time. Want all five training speeds? Read training paces explained. Moving up from the half? See what marathon you can run off your half. When you are ready, get your marathon paces below.

Sources

• Fokkema, T. et al. (2020). Training for a (half-)marathon: training volume and longest endurance run related to performance. Scandinavian Journal of Medicine & Science in Sports.
• RunnersConnect (2024). Optimal long run pace (Easy effort ~60–90 s/mile slower than 5K pace; slower is fine).
• McMillan Running. Best long run pace and the marathon long run (1–2 min/mile slower than marathon pace; fast-finish long runs).
• Runner's World (2024). The 3-hour long run rule (When to cap the longest run near 2.5–3 hours).