# How to pace a marathon

> How to pace a marathon without hitting the wall: run the first half easy, hold goal pace through the middle, and finish on feel. With a marathon pace chart.

The wall is usually a pacing mistake. Here's how to run the marathon in three deliberate phases so the early miles never cost you the last ones.

## How should you pace a marathon?

Run even, or a shade negative. Hold back through the first half until it feels almost too slow, settle into goal pace through the middle, and spend whatever is left over the closing 10K. The marathon punishes an early-fast pace harder than any other distance. The seconds you save in the first 10 miles are the seconds you will need at 35 kilometres.

Most runners do the opposite. They feel fresh, the crowd carries them, and they bank a few minutes early. That money is a debt. It comes due around 20 miles, all at once, and no amount of grit at mile 22 pays it back. The whole race is decided by discipline in the miles where you still feel great.

## What is the 10-10-10 marathon plan?

Split the 26.2 miles into three parts and run each one differently. The first 10 miles are for holding back. The middle 10 are for settling into goal pace. The last 10 kilometers are for whatever you have left. It is a plan built to keep you honest early, when honesty is cheap and the temptation to spend is strongest.

- **Miles 1 to 10: controlled and easy.** Run these a touch slower than goal pace, or right on it if goal pace feels relaxed. It should feel almost too slow. Runners will stream past you. Let them. You are protecting the back half.

- **Miles 10 to 20: settle in.** Lock onto goal pace and hold it while your legs are still fresh. No surging, no chasing. This is the stretch where a steady, boring rhythm quietly wins the race.

- **The last 10K: spend what's left.** From 20 miles home, run on feel. If you paced the first 32 kilometers right, this is where you pass the people who passed you. If you have a strong day, let the pace climb. If not, holding on is a victory too.

## What pace should you run for your marathon goal?

Pick a goal finish, then hold that pace even from the gun. The chart below gives per-kilometer and per-mile pace for the common marathon targets. Note the anchor: a sub-4:00 marathon is 9:09 per mile, exactly sub-2:00 half pace. If you know your half at that effort, you know what the marathon version should feel like. You have to hold it twice as long.

| Goal finish | Per km | Per mile |
| --- | --- | --- |
| Sub-5:00 | 7:07 /km | 11:27 /mi |
| Sub-4:30 | 6:24 /km | 10:18 /mi |
| Sub-4:00 | 5:41 /km | 9:09 /mi |
| Sub-3:45 | 5:20 /km | 8:35 /mi |
| Sub-3:30 | 4:59 /km | 8:01 /mi |
| Sub-3:15 | 4:37 /km | 7:26 /mi |
| Sub-3:00 | 4:16 /km | 6:52 /mi |

If your goal falls between these rows, use the [pace calculator](https://steadypace.ca/pace-calculator) for the
exact pace behind any finish time, or the [pace chart](https://steadypace.ca/pace-chart) for splits at every distance
in between.

## Why do you hit the wall at 20 miles?

Because you run out of stored carbohydrate. Your muscles and liver hold enough glycogen for roughly 20 miles at marathon effort, and the faster you burn it, the sooner it goes. Run the first half a few seconds per mile too fast and you spend that fuel early. Around 20 miles, the tank hits empty. Your legs turn heavy, your pace falls, and every step becomes hard.

The wall is almost always a pacing failure. The runner who hit the wall did not lack training to run 26.2 miles. They lacked the restraint to run the first 20 at the right pace. You fix the wall upstream, in the miles where you felt strong enough to ignore the plan. Reach 20 miles with fuel in the tank and there is no wall to hit.

Fast startEven pace

- 5:406:207:007:4010203042the wallDistance (km)Pace per kmThe wall is a pacing curve. Spend the first 30 km too fast and pace falls off a cliff, about **37 to 40% slower**. Hold it even and the fade is small. Onset near 30 km, pace off 37 to 40%. [Smyth 2021](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251513) (4.2M runners).

## How should you fuel a marathon?

Take carbohydrate early and often, and drink to thirst. Because the wall is a fuel problem, top up before you run low. Start fueling in the first hour, while your stomach still handles it well, and keep a steady drip going the whole way. The gel you take at mile 6 is working for you at mile 20.

**Carbs early and often.** Aim for a gel or its equivalent every 30 to 45 minutes, starting inside the first hour. Do not wait until you feel empty. By then it is too late to catch up. Practise your fueling in long runs so race day holds no surprises.

- **Drink to thirst.** Sip at the stations when you are thirsty rather than forcing fluid at every one. Over four or five hours, thirst is a reliable guide, and overdrinking causes more trouble than it solves.

## How do you hold goal pace without a screen?

The hardest part of the plan is the easy part: running the first half slower than you feel you could. Everyone around you is going faster, the pace feels wrong, and a watch only tells you after you have already drifted. You glance down, see you are 10 seconds a mile too quick, and the effort is already spent. Over 20 miles, those small overspends are exactly what builds the wall.

A continuous tone that rises when you slow and falls when you speed up catches you drifting fast in the early miles before the cost becomes real.

You run the first 32 kilometers by ear, holding just under the ceiling while your legs beg to spend. Then, over the last 10K, you let the tone climb and give back what you saved. Steady Pace also calls your splits aloud, keeps a cadence metronome, and tracks distance with fused GPS and barometer that holds up on long runs where the GPS signal drops. It is private by design: no account, no ads, no analytics, GPS anonymized on your phone, zero network connections. It is a one-time purchase with no subscription.

- [Pace calculator](https://steadypace.ca/pace-calculator): Find the goal pace behind your target finish time.
- [Negative splits](https://steadypace.ca/guides/negative-splits): Why the second half should be your faster half.
- [How to pace a half marathon](https://steadypace.ca/guides/how-to-pace-a-half-marathon): The shorter cousin, and a good rehearsal for the full.
- [Pace chart](https://steadypace.ca/pace-chart): Per-km and per-mile splits for every finish time.

**Should I run a marathon at even pace or a negative split?**

Aim for even, and be glad to finish a touch faster than you started. An even marathon, run from a controlled first half, is the safest route to your goal. A slight negative split, holding back early and building over the second half, is the ideal, but it starts with the same discipline: never spend the early miles too fast.

**What pace is a sub-4:00 marathon?**

5:41 per kilometer, or 9:09 per mile, held for the full 26.2 miles. It is the same pace as a sub-2:00 half marathon, which makes it a handy number to learn by feel. If you can hold 9:09 for a half, the marathon asks you to hold it twice as long off patient early pacing.

**How do I avoid hitting the wall?**

Pace the first 20 miles conservatively and fuel from the first hour. The wall is glycogen depletion, and it is brought on by running the early miles too fast and starting to fuel too late. Hold back until it feels almost too easy, take carbs every 30 to 45 minutes, and you reach mile 20 with fuel left to run on.

**Why does the first half of a marathon need to feel easy?**

Because the effort you save there is the effort you need at 35 kilometers. Marathon goal pace feels deceptively comfortable in the first hour, so if it feels merely comfortable rather than easy, you are already going too fast. A first half that feels almost too slow is exactly what leaves something in the tank for the finish.


---
Source: https://steadypace.ca/guides/how-to-pace-a-marathon
App Store: https://apps.apple.com/app/steady-pace/id6773682525