Plain Words Running data, in plain words.

Racing smarter

What pace is a 2:15 half marathon?

2:15:00 for the half marathon is 6:24/km (10:18/mi), held the whole way. Halfway on even pace is 1:07:30. Most watches measure the course long, so the pace you actually need on the screen is nearer 6:18/km.

The numbers on this page, in one place.
WhatNumberThe qualifier
Pace needed6:24/km (10:18/mi)even, start to finish
Halfway (even)1:07:301:08:51 on a 2% negative split
Watch pace at 1.5% overage6:18/km (10:09/mi)what the screen has to show
Distance21.0975 km (13.11 mi)the measured course, not the watch

What pace is a 2:15 half marathon?

2:15:00 over 21.0975 km (13.11 mi) is 6:24/km (10:18/mi), held from the first step to the last. There is no rounding slack in that number: run the first kilometre at 6:34/km and you have already spent ten seconds you will not get back cheaply.

2:15 asks for 6:24/km (10:18/mi) and it is a realistic goal off three runs a week. At this pace most people are running at a genuine conversational effort for the first hour, which changes what the race is about. It becomes a fuelling and mental-focus event rather than a speed one. Two practical points. Take something to eat around 60 minutes: at this duration the difference between eating and not is visible in the last 5 km. And expect the middle 5 km to be the quiet part of the course where pace drifts most, because the early excitement has gone and the finish is not close yet. That is the stretch to check your watch on.

What the splits look like

KilometreSplitElapsed
16:246:24
56:2432:00
106:241:03:59
156:241:35:59
206:242:07:59
21.09750:372:15:00

And in miles, for a course measured that way:

MileSplitElapsed
110:1810:18
310:1830:54
610:181:01:47
910:181:32:41
1210:182:03:35
13.111:082:15:00

Where should I be at halfway?

Even pace puts you through halfway at 1:07:30. Most people who finish this time went through slightly slower than that, not faster — a 2% negative split means halfway at 1:08:51 and a second half of 1:06:09.

The decision rule for race day: if you reach halfway more than 1:21 ahead of 1:07:30, you are not ahead of schedule, you are borrowing. Ease back to 6:24/km (10:18/mi) and hold it.

What if my watch measures the course long?

Almost every watch does. A half marathon that reads 1.5% long on your wrist means you have to run 6:18/km by the watch to finish in 2:15:00 by the clock. That is the pace to put on the screen, and it is why pacing off a watch's average-pace field alone tends to leave people a minute or two short.

Questions runners actually ask

Is a 2:15 half marathon a good time?
Good is a comparison, and it depends who with. Whether it is achievable for you is the answerable question: it comes down to a recent race, your weekly volume and your longest run. The race predictor puts numbers on all three.
Should I run even splits or negative splits?
Even, planned; slightly negative, executed. Going through halfway 1-2% slower than even pace costs almost nothing if you are strong at the end, and saves the race if you are not.

Sources

Changelog

  • — First published.