What is a marathon split?

A marathon split is the time you plan to spend running each segment of the race (per km or per mile). A split table lets you check your watch at each marker and know immediately whether you are on pace, ahead, or behind your goal.

What is a negative split strategy?

A negative split means running the second half of the marathon faster than the first. Research and elite race results consistently show this is the most efficient pacing approach. A common setting is a 2–5% differential — for example, running the first half at 4:20/km and the second half at 4:14/km on a 3:02 goal.

How much slower should my first half be?

A 2–4% differential is typical for trained runners. At 2% on a 4:00 finish, your first-half pace is roughly 4% slower than goal and second-half pace is 4% faster, balancing to the goal average. Beginners often do better with 1–2% to avoid blowing up.

How many km or miles is a marathon?

A marathon is exactly 42.195 km (26.2188 miles). This planner uses the exact distances: 42 full km plus a 0.195 km final segment, and 26 full miles plus a 0.2188 mile final segment.

What pace do I need to run a sub-3-hour marathon?

To finish in under 3 hours you need an average pace faster than 4:16/km (6:52/mile). Enter "3:00:00" as your goal time and the planner will generate the exact split table.

Can I print the split table?

Yes. Click the Print Table button to open a clean, print-optimized version of the splits. You can trim it to fit on a small piece of paper or tape it to your wrist during the race.

Marathon Split Planner

Name: Marathon Split Planner
Availability: InStock
Author: Nham Vu

Enter your goal marathon finish time and split strategy to get a full per-km or per-mile pace table you can print and carry on race day.

Race Settings

Goal Finish Time

min

sec

Split Unit

Split Strategy

Half-to-Half Differential (second half faster by)

Typical range: 2–5%. 1% = very slight; 10% = aggressive.

#	Dist	Pace	Split Time	Elapsed	Half

Set your goal time and click Generate Splits

Summary

Enter your goal marathon finish time and split strategy to get a full per-km or per-mile pace table you can print and carry on race day.

How it works

Enter your goal marathon finish time in hours, minutes, and seconds.
Choose km or mile splits using the unit toggle.
Select a split strategy: Even Pace keeps every split identical, Negative Split makes the second half slightly faster, Positive Split makes the first half slightly faster.
For negative/positive strategies, adjust the split differential percentage (how much faster or slower the second half runs).
Click Generate Splits to see the full split table with cumulative times.
Click Print Table to open a print-ready version of the split table.

Use cases

Plan your race-day pacing so you hit every mile marker on schedule.
Design a negative-split strategy to save energy for the final 10K.
Compare even-pace vs. positive-split plans to decide which suits your fitness level.
Print a wrist split card to carry during the race.
Calculate the exact pace per km needed to break 3, 3:30, 4, or 5 hours.
Share a split plan with a pacer or running partner.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu