How to use the race pace chart generator
- Enter the race distance and choose miles or kilometers. For a half marathon, 13.1 miles is an example.
- Enter your goal time as hours, minutes and seconds, such as 1:55:00, and the split length for each row of the table.
- Choose an even pace, a negative split (second half faster) or a positive split (second half slower), and how much the pace changes. The 2% shown is an example.
- Read the table: the pace, split time and clock time for every split. The last row always lands exactly on your goal time.
Formula
average pace P = goal time / distance
pace at distance x = P x (1 + s x (2x / D - 1)), with s negative for a negative split
time for a split from x0 to x1 = P x ((x1 - x0) + s x ((x1^2 - x0^2) / D - (x1 - x0)))
The pace moves in a straight line from the start to the finish, with the average pace in the middle. The split time is the area under that line, so the splits add up to the goal time exactly.
A half marathon in 1:55:00
The goal of 6,900 seconds over 13.1 miles is an average of 526.7 seconds per mile, or 8:47. With a 2% negative split the pace starts 2% slower at 8:56 for the first mile and ends 2% faster, with the last 0.1 mile at 8:36 per mile.
The first mile takes 536.4 seconds (8:56), the second 534.8 seconds (8:55), and the halfway point comes at 58:05, with 56:56 left for the second half. All 14 splits add up to 1:55:00. A 10 kilometer race in 50:00 at an even pace is 5:00 per kilometer, and with a 3% positive split the first kilometer takes 4:52 and the last 5:08.
Even or negative?
An even pace runs every split at the average pace, which the Pace Calculator already tabulates. What this page adds is a pace that changes in a straight line: a negative split starts slower than average and speeds up, and a positive split starts faster and slows. The size of the change is your choice. Sources disagree on which approach is best, so the tool only shows what each plan means in numbers and makes no claim about performance.
Hills, heat, wind, crowds and how you feel on the day matter more than the plan, so treat the table as a starting point that you adjust.
Related running and speed tools
Convert between pace and speed or find a finish time with the Pace Calculator, average over mixed sections with the Average Speed Calculator, and plan fuel with the Race Fueling Planner.
More planning tools
For other plans with scores, odds and balance, try the Dice Probability Calculator, Elo Rating Calculator and Balanced Team Generator.
Assumptions and limits
- The pace changes smoothly and in a straight line over the whole distance.
- The first and last splits use the same length rule as the others, with the last one shorter if the distance does not divide evenly.
- Goal times and percentages are examples until you change them.
- Terrain, weather and aid stations are not modeled.
Frequently asked questions
What is a negative split in running?
It means running the second half of a race faster than the first. In this tool a negative split starts slower than average and speeds up in a straight line to the finish.
How do I make a pace chart for a race?
Divide the goal time by the distance for the average pace, decide whether to run even or change pace, and list the time for each mile or kilometer. This page builds the table for you.
Why do the splits add up exactly to my goal time?
The pace line is built so the average pace equals the goal pace, and each split time comes from the exact area under the line, so no rounding is lost.
How large a pace change is sensible?
That depends on the runner and the course. Small changes of a few percent are easier to hold, and larger ones make the early or late miles much faster than the average.