Split planner

Plan your race with a km-by-km pacing plan: even, negative (finish faster) or progressive.

Build a per-km pacing plan (even, negative or progressive splits).

Build a per-km pacing plan for your next race: even, negative or progressive splits.

• Goal
• Target distance
• Target time
• Strategy
• Variation intensity
• Subtle
• Strong
• Pacing plan
• Avg pace
• Enter distance and time to generate your plan.

Split times: the table to know before the gun goes off

A split time is the elapsed race time at which you should pass each marker to stay on target. It is the simplest pacing tool there is: one glance at your watch at the mile or kilometre sign tells you whether you are on schedule.

To run a 3:30 marathon you need an average of 8:00 min/mile (4:58 min/km), which puts the half at about 1:45 and mile 20 at 2:40. Knowing those checkpoints is what stops the classic mistake of going out too fast, a debt that always gets collected in the second half.

Three pacing strategies

The planner builds three profiles. Pick one based on your experience and the distance:

• Even splits: the same pace from start to finish. On paper the most efficient strategy, and the one behind most marathon world records.
• Negative split: a second half faster than the first. Mentally demanding because you have to hold back early, but it is the most forgiving plan when things go wrong.
• Progressive: a gradual build across the whole race. A good compromise for runners who take a while to warm into an effort.

Adapting your splits to the course

A pacing plan calculated on the flat does not transfer unchanged to a hilly course. On a climb, the effort needed to hold pace rises sharply: it is better to give up a few seconds going up and take them back on the descent.

The right frame of mind is constant effort rather than constant pace. Study the hard sections of the course in advance and mentally adjust your split times, instead of burning matches defending a number.

Frequently asked questions

What are the splits for a 4 hour marathon?

The average pace is 9:09 min/mile (5:41 min/km). That puts 10K at 56:50, the half at 2:00:00, mile 20 at 3:03 and the finish at 4:00:00. The planner generates the full split table for any target time you enter.

Should I run a negative split?

It is the safest plan for a first marathon or whenever you doubt your preparation. Starting ten to fifteen seconds per mile slower than goal pace for the first third leaves you real margin later on. Experienced runners racing a distance they know well usually prefer even splits.

How do I pace a hilly course?

Think in effort, not in pace. Deliberately give up time on the climbs without forcing, then relax on the descents and let speed come back without wrecking your quads. On a rolling course, plan a range of split times rather than a single number.

Splits or elapsed times: what is the difference?

A split is the time taken to cover one segment, usually a mile or a kilometre. The elapsed or cumulative time is the total on the clock since the start, and it is what you compare against the mile markers during a race. Both are shown by the planner, since you pace with one and check yourself against the other.