Triathlon Split Time Target Calculator

Calculate target swim, bike, and run split times for Sprint, Olympic, Half-Ironman, and Ironman triathlons from your goal finish time and transitions.

Split Time Breakdown

Race planning in triathlon means knowing not just your goal finish time, but how to distribute effort across the swim, T1, bike, T2, and run legs.

Standard triathlon distances and typical finish times:

Format Swim Bike Run Beginner Competitive
Sprint 750 m 20 km 5 km 1:30-2:00 55-75 min
Olympic 1,500 m 40 km 10 km 2:30-3:30 1:50-2:20
Half Ironman (70.3) 1,930 m 90.1 km 21.1 km 5:30-7:00 4:00-5:00
Full Ironman 3,860 m 180.2 km 42.2 km 12:00-16:00 8:30-11:00

The 70.3 and Ironman distances are usually quoted rounded, as 1.9 km and 90 km. The exact figures come from the imperial originals, 70.3 and 140.6 total miles. Over a full Ironman that rounding is worth about four minutes on the bike alone, so the precise numbers are what this page uses.

Typical split distributions (% of total race time):

  • Swim: 10-15% of total
  • T1: 2-4% of total
  • Bike: 45-55% of total
  • T2: 1-2% of total
  • Run: 30-38% of total

Transitions here are fixed at 2.5% for T1 and 1.5% for T2, which lands mid-range for both. They are not adjustable because at every level they are a rounding error next to the bike split, and pretending otherwise makes the plan look more precise than it is.

Pacing philosophy: The bike sets up the run. Many triathletes race the bike at 85-90% of max effort and then find the run impossible. A conservative bike lets you run at close to standalone pace. The goal is the fastest TOTAL time, not the fastest single split.

Worked example, Olympic distance, goal 2:15:00:

Leg Share Target Pace it implies
Swim 12% 16:12 1:05 per 100 m
T1 2.5% 3:23
Bike 50% 1h 7m 30s 35.6 km/h
T2 1.5% 2:02
Run 34% 45:54 4:35 per km

Look at what that actually asks for. A 2:15 Olympic split evenly is a 35.6 km/h bike and a 4:35/km run off it, which is competitive age-group territory rather than a first-race target. That is the point of working backwards: the goal time tells you whether the plan is a plan or a wish.

Adjust the percentages to your relative strengths. A strong cyclist gives more of the day to the bike, a strong runner pushes for a faster run split, and the leftover always lands on the run because that is the leg the other four are taken out of.


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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.

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