Split strategy

How the split planner works

Enter a race distance and a goal time, then choose how evenly you want to run it. The slider tilts your pace in a straight line from the start to the finish:

• Even means every split is the same.
• Negative split means you run the second half faster than the first. Slide right, and you start a few percent slower than your average pace and finish a few percent faster.
• Positive split means you start fast and slow down. Slide left.

After tilting, the plan is rescaled so that the splits add up exactly to your goal time. You can see the pace for each split, the elapsed time at each marker, and your first-half and second-half times.

Why most runners should aim for even or slightly negative

Starting too fast is the most common racing mistake. Early speed feels easy, but it borrows from the final miles, and slowing down costs more time than a cautious start would have. Many record performances are run with remarkably even splits or a slight negative split, and a gentle negative split is a forgiving target for everyone else. Read more in negative splits explained.

Take your plan with you

• Print splits creates a clean two-column sheet you can fold onto a wristband or tape inside your bib.
• Wallpaper saves your splits as a phone lock-screen image so you can check them at a glance.
• Copy link encodes your distance, goal and strategy in the web address so you can reopen or share the same plan.

Limits

• The plan assumes a flat, steady course. On hills, pace by effort and let the clock float, then settle back toward the plan on level ground.
• Heat, wind and crowded starts will change your real splits. Build in a little slack for the first mile.
• A negative split only works if the goal is realistic. Check it with the race predictor first.