How to Pace a Marathon Properly

One of the biggest mistakes runners make in the marathon is starting too fast. The marathon is rarely limited by speed - it is limited by pacing, fuelling and fatigue resistance. Good pacing can make the difference between a strong final 10 km and a long, painful walk.

The most effective marathon pacing strategy for most runners is even pacing or very slightly negative splitting. This means running the second half of the race at the same pace or slightly faster than the first half. Many runners go out too fast in the first 10 km because the pace feels easy early on, but the cost of that effort is usually paid for after 30 km.

To pace a marathon properly, you should know your target finish time and convert that into a pace per kilometre or per mile. This becomes your reference pace for the race. Small variations due to hills, aid stations and crowds are normal, but large pacing swings usually lead to fatigue later in the race.

A simple way to calculate your required pace is to use a pace calculator and work backwards from your target finish time. This allows you to understand exactly what pace you need to hold from the start of the race.

You can calculate your required pace using the Pace Calculator on this site.

Pacing is also closely linked to fuelling. If you run too fast early in a marathon, you will burn more carbohydrate and are more likely to run out of energy later in the race. Good pacing and good fuelling should always be planned together.

Marathon pacing is not about running as fast as possible at the start. It is about running at a pace you can sustain for the entire distance. The goal is not to feel good at halfway - it is to still be running strongly in the final 10 km.

If you need help planning pacing and training, for any event from a 5k to an Ironman triathlon, see my coaching page.