Half Marathon Pace Chart in KM: Build a Race-Ready Plan

The short answer

A half-marathon pace chart turns a finish goal into an average kilometre pace, not a promise that every kilometre should be identical. Start with goal time ÷ 21.0975 km, round to a pace you can read while moving, and write checkpoints at 5K, 10K, 15K, 20K, and the finish. Then adjust effort for the verified course, weather, crowding, and current fitness.

The half marathon is 21.0975 km.1 A chart can make the arithmetic clear. It cannot prove that the goal is realistic, account for a long hill, diagnose symptoms, or tell you to chase a lost split.

Use this finish-time pace chart

These are even-pace arithmetic anchors. Small differences come from rounding.

Use the running pace calculator for another finish time. Keep the chart and calculator as arithmetic tools; use completed training to decide which row belongs in the race plan.

Check whether the row is earned

Choose a recent, comparable piece of evidence:

• a controlled race or time trial;
• a sustained workout with honest recovery;
• long runs that finish without a large form or pace collapse;
• several repeatable weeks, not one exceptional day;
• similar terrain and environmental conditions where possible.

Half-marathon pacing research shows that pacing behaviour differs across athletes and finish levels.2 A population pattern is not an individual prescription. If the selected row requires a pace you have not held under controlled conditions, use it as a question for training rather than a race-day order.

Build three pace bands

One exact number becomes fragile when a course or day changes. Write three bands:

For a two-hour goal, for example, 5:41/km is the arithmetic average. The first kilometres might be slower while the field opens, the middle kilometres might sit near the working band, and the final kilometres might become faster only if effort remains controlled. Do not spend the upper band to repair a 20-second delay at the first turn.

Convert the course into effort decisions

Open the official course map and elevation profile. Record:

1. start width and likely crowding;
2. sustained climbs and descents;
3. tight turns or mixed surfaces;
4. exposed wind or heat sections;
5. aid-station locations;
6. timing mats and reliable landmarks.

Running uphill and downhill changes energy cost and mechanics.4 On a climb, let pace slow while effort stays bounded. On a descent, use smooth cadence and stable form rather than forcing the chart. The goal is an average over the whole course, not a perfect row of identical splits.

Use a five-checkpoint card

Write one decision beside each checkpoint:

This is more useful than writing “make up time.” A late decision should use current evidence, not anxiety about an earlier split.

Rehearse without racing every long run

Use a bounded rehearsal:

• warm up as you normally would;
• run an easy opening segment;
• practise a short block near the working band;
• record breathing, perceived effort, form, terrain, weather, and recovery;
• stop the pace block if it becomes a test rather than practice.

Do not turn every long run into a half-marathon simulation. The half-marathon training hub and half-marathon course-profile pacing plan connect pace work to the wider build.

Adjust for heat, wind, and GPS error

Heat increases physiological strain, and acclimation guidance supports adjusting training and competition decisions to conditions.6 Use effort, aid access, and symptoms rather than treating the cool-weather chart as a command.

GPS can drift near tall buildings, trees, tunnels, turns, and crowded starts. Compare the watch with official kilometre markers and elapsed time. If one split looks implausible, wait for another reliable marker. Do not surge because a watch briefly reports the wrong pace.

For wind, protect effort into a headwind and avoid overstriding with a tailwind. For rain or poor footing, prioritise traction and safe turns. The chart survives these changes because it is a planning anchor, not a rigid controller.

Know when to abandon the goal row

Slow down, stop, or seek help for:

• chest pain, fainting, confusion, or severe breathing difficulty;
• pain that changes normal movement;
• loss of coordination or repeated stumbling;
• chills, worsening dizziness, or other heat-illness warning signs;
• repeated vomiting or inability to keep down familiar fluid;
• a pace that now requires an uncontrolled effort far before the finish.

Fluid guidance is individual, and over-drinking can be dangerous.7 Do not use the chart to force a fluid or carbohydrate schedule you have not rehearsed.

Race-week checklist

• Confirm the exact official distance, course, and start instructions.
• Print or save the five checkpoints.
• Write conservative, working, and upper pace bands.
• Check the current forecast and exposure.
• Pair the chart with a rehearsed half-marathon fueling plan.
• Set the watch display before race morning.
• Decide which symptoms or movement changes end the pace goal.
• Keep the final sessions familiar and reduce fatigue.

Frequently asked questions

Should every kilometre match the chart?

No. Use the chart to understand the average and checkpoints. Let pace vary with terrain, congestion, weather, and safe effort.

Should I start faster to create a buffer?

Usually not. An early buffer can cost more later than it saves. Start inside a controlled band and let the race become more specific after the field and breathing settle.

What if I miss a 5K checkpoint?

First identify why. Crowding, a hill, GPS error, heat, or an unrealistic goal require different responses. Do not automatically surge.

Is a pace calculator enough to set my goal?

No. It solves arithmetic. Recent comparable performance, repeatable training, health, course, weather, and recovery determine whether the output is useful.

Safety boundary

This chart is educational and not medical advice, a diagnosis, an individualized prescription, or a guaranteed finish time. Use current event instructions and qualified medical or coaching support where appropriate.

26weeks.ai keeps your finish line, completed training, recovery, schedule, and near-term decisions connected in one adaptive week. Start training now.

References

1. World Athletics. Half marathon discipline overview and official distance. (World Athletics)
2. Santos-Lozano A, et al. Pacing profiles of 208,760 half-marathon finishers. (PubMed)
3. Casado A, et al. Pacing behaviour in endurance running: systematic review. (PubMed)
4. Minetti AE, et al. Energy cost of walking and running at extreme slopes. (PubMed)
5. Vernillo G, et al. Biomechanics and physiology of uphill and downhill running. (PubMed)
6. Racinais S, et al. Exercise-heat acclimation and heat-illness prevention. (PubMed)
7. American College of Sports Medicine. Exercise and fluid replacement. (PubMed)
8. Third International Exercise-Associated Hyponatraemia Consensus. (PubMed)