Half Marathon Pace Calculator
Enter your goal finish time to find the pace you need to hold, or enter a pace to see your projected finish time. The calculator shows per-mile and per-km pace, speed in km/h and mph, your halfway split, and a full kilometre-by-kilometre or mile-by-mile split schedule. Metric and imperial units are both supported and switch instantly.
How to use this calculator
Choose a solve mode from the "Solve for" dropdown. In Pace mode, enter your goal finish time in h:mm:ss format (for example, 1:45:00 for one hour forty-five minutes) and the calculator tells you the per-km and per-mile pace you need to hold. In Finish time mode, enter your target pace in minutes and seconds, select whether it is per km or per mile, and the calculator projects your finish time. Both modes also show your halfway split at 10.55 km, your average speed, and suggested training zone paces. The splits schedule below the result shows your elapsed and remaining time at every kilometre marker.
Half marathon pace formula
The core relationship is: Finish Time = Pace x Distance. For a half marathon the distance is 21.0975 km (13.1094 miles). Given a goal time T in seconds and the distance D in km, the required pace is P = T / D seconds per km. To convert seconds per km to seconds per mile, multiply by 1.60934. To find finish time from pace, multiply pace (in seconds per unit) by the distance in those same units. For example, a 5:41 /km pace (341 seconds per km) over 21.0975 km gives 341 x 21.0975 = 7,194 seconds = 1:59:54, just under the two-hour barrier.
Training paces explained
The calculator derives three training paces from your goal half marathon pace. Easy pace (also called recovery or base pace) is roughly 60-90 seconds per km slower than your race pace; this is the pace for the majority of your weekly mileage and long runs. Tempo or threshold pace is about 5-10 seconds per km faster than half marathon pace; it trains your lactate threshold and is typically held for 20-40 minute blocks. Interval pace is about 30-40 seconds per km faster than race pace and is used for short hard repeats (400 m to 1 km) to build VO2max. These are estimates based on McMillan and Daniels running formula research; your actual zones depend on your current fitness and should be confirmed with a coach or fitness test.
Pacing strategy for race day
The most common half marathon mistake is going out too fast in the first 5 km. A common finding in race data is that runners who run an even or slight negative split (second half slightly faster) finish with more energy and post faster times than those who run a positive split. A simple strategy is to run the first 5 km at 5-10 seconds per km slower than goal pace, settle into goal pace from km 5-17, then run by feel over the final 4 km. Keep an eye on your elapsed time at 5 km, 10 km, and 15 km waypoints - the splits table in this calculator gives you target elapsed times for each marker.
Half marathon finish time benchmarks
| Finish time | Pace /km | Pace /mile | Runner level |
|---|---|---|---|
| Under 1:05 | Under 3:05 | Under 4:58 | World-class elite |
| 1:05 - 1:15 | 3:05 - 3:33 | 4:58 - 5:43 | National/semi-elite |
| 1:15 - 1:30 | 3:33 - 4:16 | 5:43 - 6:52 | Competitive club |
| 1:30 - 1:45 | 4:16 - 4:59 | 6:52 - 8:01 | Strong recreational |
| 1:45 - 2:00 | 4:59 - 5:41 | 8:01 - 9:09 | Recreational runner |
| 2:00 - 2:20 | 5:41 - 6:39 | 9:09 - 10:41 | Intermediate |
| 2:20 - 2:45 | 6:39 - 7:48 | 10:41 - 12:33 | Beginner-intermediate |
| 2:45 - 3:00 | 7:48 - 8:31 | 12:33 - 13:43 | Beginner |
| Over 3:00 | Over 8:31 | Over 13:43 | Casual/walker-runner |
Typical finish time ranges by ability level for adult runners, based on large-race data. Times vary by course profile and conditions.
Frequently asked questions
What is a good half marathon time for a beginner?
Most first-time half marathon finishers complete the distance in 2:20 to 3:00. Finishing at any time is a significant achievement. Once you have one race under your belt, many runners aim to break 2:30 in their next attempt, then work toward 2:00 as a medium-term goal.
How do I convert my pace from per mile to per km?
Divide your per-mile pace (in seconds) by 1.60934 to get per-km pace, or multiply your per-km pace by 1.60934 to get per-mile pace. For example, an 8:00 /mile pace is 480 seconds per mile, divided by 1.60934 = 298 seconds = 4:58 /km. This calculator does the conversion automatically in both solve modes.
What pace do I need for a 2-hour half marathon?
To finish in exactly 2:00:00, you need to average 5:41 per km (9:09 per mile), which is a speed of 10.55 km/h (6.55 mph). In practice, most coaches recommend targeting 5:38-5:40 /km to build in a small buffer for hills, turns, water stations, and uneven splits.
What is a negative split in a half marathon?
A negative split means running the second half of the race faster than the first. For a half marathon this means passing the halfway mark (10.55 km) slightly after half your goal time, then picking up the pace in the second half. Research consistently shows that even pacing or a slight negative split produces faster finish times and feels better physically than going out hard and slowing down (a positive split).
How do I use this calculator to plan my splits?
Enter your goal time in Pace mode (or your target pace in Finish time mode) and scroll to the splits table. The table shows your elapsed time and remaining time at every kilometre marker from 1 km to 21.1 km assuming even pacing. Print or screenshot the table before race day and check your watch or timing mat readings at the 5 km, 10 km, and 15 km marks to stay on target.
Can I use this calculator for other race distances?
This calculator is specifically designed for the half marathon distance of 21.0975 km (13.1094 miles). For a full marathon, 10 km, 5 km or custom distance, you would need a general running pace calculator that accepts any distance. The training zone paces shown here (easy, tempo, interval) are also specific to half marathon fitness and will differ slightly for other target distances.