Marathon Pacing - What Time to Expect in the Marathon

by Benjamin
(Berkeley, CA, U.S)

I have got a question about marathon pacing. I've been working out for a good 3 years now on and off. In high school I ran cross country and played soccer. My best 5k was 18min something.

For the past month I've been running / cross-training about 6 days a week for at least and hour a day. I always have plenty of energy left after my runs and when I jump rope for an hour or play soccer. I feel great.

I signed up for a marathon (a month from now), and I'm wondering how long it might take me to finish. Right now I can finish 5k runs in the 18 min range, and once a week I run a 10 mile trail.

Answer by Dominique:
Hi there,
Thanks for your question about what your marathon pacing should be.

I see you are reasonably fit.

Exercise six days a week, an hour per day is very good.

However, a marathon is a serious undertaking.

I'll break it down as follows:

1. A reality check
2. A plan for your marathon
3. A better way to train for your next marathon
4. How to work out what time to expect on a marathon

A Reality Check

Apologies if the below comes as a shock. You are underprepared for a marathon. Eventhough you have built up fitness and do a lot of exercise, a marathon requires a lot more, particularly in terms of your long run.

Ideally you would have built up your long run to a 2.5-3 hour effort, doing about 20 miles.
The best preparation for a marathon is in doing a weekly consistent long run of 120 to 180 minutes, preferably backed up by a mid-week mid-long run of at least 90 minutes.

A Plan for Your Marathon

Given you have not done the training for it, your best bet to finish this marathon is use really conservative marathon pacing, i.e. to run it at an easy pace, potentially adding in walking breaks from the beginning, e.g. alternating 7 minutes running, 3 minutes walking.

When you ignore this advice, the second half of your marathon will be very tough and you will be forced to walk the remainder at some point.

As far as time goals go, I'd ignore them for this marathon. I'd expect you to cover it in 4+ hours.

A Better Way to Train for Your Next Marathon

First of, I'd highly recommend reading the Marathon Training Tips section on this website, including much of the Q&A. Spend some time analysing it all and reading through it. You'll come to the conclusion that proper marathon training is tough and that the marathon deserves a level of respect.

In my views, if you really want to have a crack at racing a marathon, I recommend building up your running more until you are comfortable with a consistent long run of 13 miles. You would have done some 13-15 mile long runs and are able to do those without too many issues. Then you start an 18-week marathon training program.

What many of us do not realise that in order to do a proper marathon, you basically first need to do the training to get ready for marathon training.

How to Work Out What Time to Expect on a Marathon

When you go to the Marathon Calculator Page on this website you find some useful calculators. You could plug in your 5k time and see that it is within your abilities to run a marathon in less than three hours.

But a 5k is not the best predictor for a marathon. I'd recommend longer races, such as a half marathon, rather than a 5k. Even then, your marathon effort needs to be backed up by the right training to achieve that marathon pace goal.

So sorry if this has been a bit of a sobering message, but still, I hope it helps.
Best of luck.
Kind regards,
Dominique