Running Splits Calculator

Running splits are the times recorded for each segment of a race or training run — typically each mile or kilometer. Calculating target splits from a goal finish time allows runners to execute an even-pace, negative-split, or banked-time strategy.

Even-split formula: Split Time = Goal Finish Time ÷ Total Distance

Pace formula: Pace (min/mile) = Total Time (minutes) ÷ Distance (miles) Pace (min/km) = Total Time (minutes) ÷ Distance (km)

Converting pace to speed: Speed (mph) = 60 ÷ Pace (min/mile) Speed (km/h) = 60 ÷ Pace (min/km)

Negative split strategy (recommended for races): Run the first half at 2–5% slower than goal pace; run the second half at or slightly faster than goal pace.

First-half pace = Goal Pace × 1.02–1.05 Second-half pace = Goal Pace × 0.97–1.00

Common race distances and paces for popular finish times:

5K (3.107 miles):

• 20:00 finish = 6:26/mile pace
• 25:00 finish = 8:03/mile pace
• 30:00 finish = 9:39/mile pace

Half Marathon (13.109 miles):

• 1:30:00 finish = 6:52/mile pace
• 2:00:00 finish = 9:09/mile pace
• 2:30:00 finish = 11:27/mile pace

Marathon (26.219 miles):

• 3:00:00 finish = 6:52/mile pace
• 3:30:00 finish = 8:01/mile pace
• 4:00:00 finish = 9:09/mile pace
• 5:00:00 finish = 11:27/mile pace

What each variable means:

• Even splits — identical time per mile/km throughout the race; the simplest strategy
• Positive split — running the first half faster; leads to fatigue and slow second half; most common amateur mistake
• Negative split — running the second half faster; scientifically optimal for performance and finish time

Worked example: Goal: finish a half marathon in 1:45:00 (105 minutes).

Even pace = 105 min ÷ 13.109 miles = 8:00/mile (7:59/mile exact)

Negative split plan:

• Miles 1–6.5: 8:12/mile (2.5% slower)
• Miles 6.5–13.1: 7:54/mile (1% faster than goal)

Mile-by-mile splits: 8:12, 8:12, 8:12, 8:12, 8:12, 8:12, 8:00, 7:54, 7:54, 7:54, 7:54, 7:54, 7:54 (final 0.1 miles at max effort) Projected finish: 1:44:52 — 8 seconds under goal.