Half Marathon Split Calculator
Enter your target half marathon time and get mile-by-mile splits with your choice of pacing strategy. Even, negative, or positive splits with checkpoint times and an on-pace tracker.
Calculate Your Splits
Enter your target finish time and choose a pacing strategy
Avg Pace/Mile
9:09
Avg Pace/Km
5:41
Strategy
even
Key Checkpoint Times
5K
28:26
Mile 3.1
10K
56:53
Mile 6.2
10 Miles
1:31:32
Mile 10.0
20K
1:53:45
Mile 12.4
Am I On Pace?
Enter your actual time at a checkpoint to see if you are ahead or behind your target pace. This tool accounts for your target finish time entered above.
Common Half Marathon Target Splits
Reference table showing mile-by-mile splits for the most popular half marathon goal times, using even pacing. Print this page or screenshot the table for quick race day reference.
About This Half Marathon Split Calculator
This is a free half marathon split calculator designed specifically for the 13.1 mile distance. Unlike generic split calculators, this tool is tailored to half marathon racing with features like pacing strategy selection (even, negative, or positive splits), key checkpoint times at 5K, 10K, 10 miles, and 20K, and an on-pace tracker that tells you whether you are ahead or behind at any checkpoint.
The calculator supports both mile and kilometer splits and includes a pre-calculated reference table for common goal times (1:30, 1:45, 2:00, 2:15, 2:30). Published by Motera, a gamified running app for iOS.
Train Smarter, Race Faster
Even splits come from consistent training, and consistent training comes from runs you actually want to do. Motera turns every build week session into a territory mission on a real city map.
MoteraWhy Negative Splits Work for 13.1 Miles
A half marathon is long enough for pacing errors to compound, but short enough that a conservative start still leaves real time on the table if you never speed up. Running the second half faster than the first preserves glycogen and delays the muscular fatigue that causes the last-5K fade, which is why the strategy shows up repeatedly in race-winning performances and in exercise physiology research.
A 2024 physiology review of marathon pacing data found that runners who ran even or slightly negative splits consistently outperformed runners who went out fast and faded, and that the effect held across ability levels, not just among elites. The same logic applies at half marathon distance, just compressed into a shorter window where the first 5K matters more and there is less time to recover from an early mistake.
Read the pacing physiology review (PMC)Negative Split Mile-by-Mile Tables
These tables apply the same 8 second per mile offset used in the calculator above (8 seconds slower than average through mile 7, 8 seconds faster than average from mile 8 to the finish) to three of the most common half marathon goal times. Use them as a printable pacing card if you would rather not check the interactive tool mid-race.
1:45:00 Goal, Negative Split Pacing
2:00:00 Goal, Negative Split Pacing
2:15:00 Goal, Negative Split Pacing
The 5K-Segment Race Day Playbook
Breaking 13.1 miles into five checkpoints makes a negative split easier to execute because you only have to make one decision at a time. Here is what each segment is asking of you.
- 1
Miles 0 to 5K (0 to 3.1)
Hold back on purpose
Run 8 to 10 seconds per mile slower than goal pace even though you feel fresh. Adrenaline and the crowd make this the easiest mile to blow. Check your watch at the 5K arch and confirm you are behind your even-split time by roughly 25 to 40 seconds. That is the plan working, not a mistake.
- 2
5K to 10K (3.1 to 6.2)
Settle into goal pace
Bring your pace down to exactly your target average. This is where you find your rhythm and start passing runners who went out too fast in the first mile. Take your first fueling (gel or chews) as you cross 10K if your race is over 90 minutes.
- 3
10K to 15K (6.2 to 9.3)
Stay locked in, resist surging
The middle third is mentally the hardest because the start feels far behind and the finish still feels far away. Do not surge to make up time or slow down out of boredom. Hold your goal pace and break the segment into 1K chunks if your mind wanders.
- 4
15K to 20K (9.3 to 12.4)
Start the negative split push
If you followed the conservative start, you should have 10 to 15 seconds per mile in reserve. Begin easing your pace down here, 3 to 5 seconds per mile at a time. Check your cumulative time against the 20K checkpoint in the table above to confirm you are on or ahead of schedule.
- 5
20K to finish (12.4 to 13.1)
Empty the tank
The final 0.9 miles is where the conservative start pays off. Runners who went out too fast are fading around you. Hold or increase your pace through the last turn. This is the only segment of the race where perceived effort should exceed goal pace effort.
Even, Negative, or Positive: Which Should You Run?
The calculator above lets you toggle between all three strategies because the right choice depends on your training, the course, and the weather. Coaching resources like the McMillan pace charts and pacing guidance from Runner's World both point to the same conclusion: even and negative splits outperform positive splits for almost every runner, on almost every course.
Even splits
Pros
- Simplest to execute and track against a watch
- Lowest risk of blowing up in the final miles
- Works well in hot or hilly conditions where effort matters more than pace
Cons
- Leaves a small amount of time on the table versus a well-executed negative split
- Requires accurate goal-pace knowledge from recent training
Negative splits
Pros
- Produces the fastest results for well-trained runners on flat, cool courses
- Glycogen stays available longer, delaying the late-race fade
- Passing tired runners in the last 5K is a large psychological boost
Cons
- Requires discipline to hold back through mile 1, which is harder than it sounds
- A start that is too conservative wastes fitness if you never make up the time
Positive splits
Pros
- Feels natural since it matches how fatigue builds during the race
Cons
- Almost always produces a slower finish time than even or negative pacing
- The late-race slowdown is usually far larger than the early-race time gained
- Rarely a deliberate strategy, more often a symptom of starting too fast
Pacing Mistakes That Wreck a Negative Split
Starting with the fastest corral you can sneak into
Lining up ahead of your pace group means weaving through slower runners for the first mile, which burns energy and forces surging. Line up with your actual goal pace, even if that means starting further back.
Chasing instant GPS pace instead of lap pace
Instant pace jumps around wildly near tall buildings, tunnels, and tree cover. Set your watch to show lap or average pace so you are reacting to real trends, not GPS noise.
Banking time in the first 5K
Running the opening miles faster than goal pace to build a cushion is the single most common way half marathons fall apart. The energy cost of an early fast mile is disproportionate to the time it saves.
Ignoring the checkpoint math mid-race
A pacing plan only works if you actually check it. Glance at your cumulative time at each 5K arch and compare it to your target splits table. Small corrections at 10K are easy. Large corrections at mile 11 are not.
Skipping the practice negative split in training
Race day is the wrong place to attempt a pacing strategy for the first time. Run at least one long run or tempo workout in training where you deliberately run the second half faster than the first.
Watch: Training to Run Negative Splits
The Running Channel breaks down how to train your body and your pacing discipline to actually run a negative split half marathon on race day, not just plan one on paper.
Frequently Asked Questions
What is a good half marathon split strategy?
The best strategy for most runners is even splits or slight negative splits. Even splits mean running every mile at the same pace. Negative splits mean running the second half 5 to 15 seconds per mile faster than the first half. Starting conservatively and finishing strong almost always produces a better time than going out fast and slowing down.
How do I calculate my half marathon splits?
Divide your target finish time by 13.1 to get your average pace per mile. For even splits, each mile should take that same amount of time. For negative splits, add 5 to 10 seconds to your average for the first half and subtract the same from the second half. The calculator on this page does all of this automatically.
What are the key checkpoints in a half marathon?
The most useful checkpoints are 5K (mile 3.1), 10K (mile 6.2), 10 miles, and 20K (mile 12.4). Most races have clocks at these distances. Knowing your expected cumulative time at each checkpoint helps you stay on pace without constantly checking your watch.
What is a negative split in a half marathon?
A negative split means your second half is faster than your first half. In a half marathon, this usually means running the first 6 to 7 miles about 5 to 15 seconds per mile slower than goal pace, then gradually picking up to goal pace or faster for the remaining miles. It requires discipline early on but usually produces a faster overall time and a much better race experience.
How do I know if I am on pace during a half marathon?
Check your cumulative time at mile markers against your pre-calculated splits. If you are within 10 to 15 seconds of your planned cumulative time, you are on pace. Being more than 30 seconds ahead in the first 5 miles usually means you are going too fast. Use the "Am I on pace?" tool on this page to check at any checkpoint.
Should I use mile splits or km splits for a half marathon?
Use whatever your race course marks. In the US, most half marathons mark miles. In Europe and Australia, most mark kilometers. If you train in miles, use mile splits. If the race marks km but you think in miles, write down both and check whichever markers appear first.
What half marathon split times do I need for a 2 hour finish?
A 2:00:00 half marathon requires an average pace of 9:09 per mile. With even splits, every mile should be about 9:09. The cumulative time at mile 5 would be 45:47, at mile 10 would be 1:31:34, and the finish at 13.1 miles would be 2:00:00. The pre-calculated table on this page shows these splits for many common goal times.
What happens if I go out too fast in a half marathon?
Going out too fast in a half marathon (positive splitting) causes premature fatigue, usually hitting between miles 9 and 11. Your pace per mile can slow by 30 to 60 seconds or more in the final miles. A 5 second per mile gain in the first half often costs 15 to 20 seconds per mile in the second half. Starting conservatively is almost always faster overall.
