By Zencalcy Editorial TeamLast reviewed About us
Work out the steady pace a half marathon goal time requires. A half marathon is 21.0975 km, or about 13.1 miles, so the finish time divided by that distance gives the average pace you need to hold.
Find the average pace for your half marathon goal time.
pace (per km) = goal time ÷ 21.0975 pace (per mile) = pace (per km) × 1.609344 split = pace × split distance
The pace is an even split across the whole race. On a flat course this is a solid plan, while a hilly course usually rewards a slightly slower first half and a stronger finish.
| Symbol | Meaning |
|---|---|
| goal time | Your target half marathon finish time in hours and minutes. |
| pace | Average time per kilometre or per mile at that finish time. |
| split | The time you would reach a shorter distance at the same pace. |
A 1:45:00 half marathon needs an average pace of about 4:59 per km, which is about 8:01 per mile. At that pace you would pass 5K in 24:53 and 10K in 49:46.
The half marathon spans 21.0975 kilometres, or 13.1 miles, and the calculator takes your target finish time and divides it by that distance to produce minutes per kilometre and per mile. This is the average pace required, the speed you would need to hold from the start line to the finish without variation.
The half sits between the ten kilometre and the full marathon in its demands. It is long enough that endurance matters but short enough that a pace close to your ten kilometre speed may be sustainable, so many runners find their half pace only a little slower than their shorter race pace.
Because the half is short enough to run hard throughout, even pacing pays off more here than in the marathon, where the late miles dominate. Starting a few seconds per kilometre too fast can be recovered early but rarely late, so the first few kilometres are the easiest place to give away your target.
A useful rhythm is to run the opening segment at or just under goal pace, hold it through the middle, and lift only in the final kilometres if you still control your breathing. The average you entered assumes no walking and no stops, so factor in any planned water breaks.
Continue with the Marathon Pace Calculator, Race Time Prediction Calculator, or the Running Cadence Calculator — or browse more running tools and all sports calculators.
No. You can normally hold a slightly faster half marathon pace than a full marathon pace, so a realistic half goal is usually quicker per kilometre than a full marathon goal of the same effort.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026