What is the best half marathon pacing strategy?

Even effort with a slight negative split. Start the first 3 miles 5-10 seconds per mile slower than goal pace, run miles 4-10 at goal pace, then push the final 5K if you feel strong.

Should I fuel during a half marathon?

For races under 90 minutes, pre-race nutrition is usually sufficient. For races over 90 minutes or in heat, take 20-30g of carbs around miles 5-6 and 8-9. Practice this in training first.

How fast should the first mile of a half marathon be?

5-10 seconds per mile slower than goal pace. The adrenaline of race morning makes the first mile feel easy. Discipline here prevents glycogen depletion and pace collapse after mile 10.

What 10K time predicts a half marathon?

Roughly double your 10K time plus 3-8 minutes for trained runners. A 50-minute 10K suggests 1:43-1:48 half marathon potential with proper endurance training.

How do I avoid hitting the wall in a half marathon?

The half marathon wall is usually glycogen depletion from starting too fast, not true marathon-style bonking. Conservative early pacing and optional mid-race fueling prevent it.

How to Pace a Half Marathon: The Complete Strategy Guide

Quick Answer

Pace a half marathon with even effort and a slight negative split. The first 3 miles should feel conservative. Miles 4-10 are goal pace. Miles 11-13.1 are where the race is won or lost—hold pace if strong, resist panic if struggling.

Physiology

A half marathon is run at roughly 80-88% of VO2max for trained runners, near or slightly below lactate threshold. Glycogen depletion is a factor after mile 10 if pacing is too aggressive early.

Mile-by-Mile Strategy

Miles 1-3: Discipline

Start 5-10 seconds per mile slower than goal pace. The crowd will feel slow. Trust the plan. Banking time here costs you at mile 11.

Miles 4-7: Rhythm

Settle to goal pace. This should feel comfortably hard. Focus on relaxed form and steady breathing.

Miles 8-10: Execute

Maintain goal pace. Mental fatigue often appears here before physical fatigue. Stay present and hit your nutrition plan.

Miles 11-13.1: Race

Increase effort if pace is holding. If pace is slipping, shorten stride and maintain cadence rather than forcing speed. The final mile is maximum sustainable effort.

Half Marathon Pacing by Goal Time

Goal	Per mile	Per km	5K split
1:20:00	6:06	3:47	18:53
1:30:00	6:52	4:16	21:15
1:45:00	8:01	4:59	24:45
2:00:00	9:09	5:41	28:18
2:15:00	10:18	6:24	31:53
2:30:00	11:27	7:06	35:27
3:00:00	13:44	8:31	42:33

Fueling and Hydration

Timing	Fueling	Hydration
Pre-race (2-3 hr)	30-60g carbs	400-600 mL water
Mile 5-6	Optional gel (20-25g)	Small cup at aid station
Mile 8-9	Gel or chews if used	Small cup at aid station
Races over 2:00	30g carbs per hour	Every 15-20 min

Adjusting for Conditions

Heat and humidity

Slow goal pace about 1-3% per 5°F (3°C) above 60°F (15°C), based on common heat-performance models. Use the Humidity Calculator for a course-specific estimate rather than a fixed rule.

Hilly courses

Run by effort on climbs. A 30-second slower uphill mile followed by a 15-second faster downhill often produces better overall time than forcing pace on hills.

Plan Your Half Marathon

Generate mile splits and factor in weather conditions before race day.

Split Calculator Half Marathon Pace Chart

Editorial references

Pacing strategy and athletic performance

Abbiss, C.R. & Laursen, P.B. (2008). Sports Medicine, 38(6), 441-463.

Carbohydrate feeding during exercise

Burke, L.M. et al. (2011). Journal of Sports Sciences, 29(S1), S17-S27.

Pfitzinger, P. & Douglas, S. (2009). Advanced Marathoning (2nd Edition). Human Kinetics.