Ironman Pacing Calculator

Plan your Ironman race day with precision. Enter your swim pace (per 100m), bike speed (km/h), and run pace (per km) to get projected segment times and a total finish time for the full 140.6-mile distance. You can also input your FTP test power data to get recommended bike wattage targets for the 180km bike leg. A complete pacing breakdown for swim, bike, and run — all in one place.

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Minutes component of your pace per 100 metres

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Seconds component of your pace per 100 metres

km/h

Your average cycling speed on the 180 km bike leg

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Minutes component of your run pace per kilometre

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Seconds component of your run pace per kilometre

min

Estimated time in transition from swim to bike

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Estimated time in transition from bike to run

W

Optional: Used to estimate your FTP and race bike power targets

Choose your intended effort level on the bike

Results

Estimated Finish Time

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Swim Time (3.8 km)

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Bike Time (180 km)

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Run Time (42.2 km)

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Total Transition Time

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Estimated FTP

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Recommended Ironman Bike Power

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Race Time Breakdown

Results Table

Frequently Asked Questions

What are the official Ironman race distances?

A full Ironman consists of a 3.8 km (2.4 mile) swim, 180 km (112 mile) bike ride, and a 42.2 km (26.2 mile) marathon run. The total distance is 226 km (140.6 miles). T1 and T2 transitions between segments also count toward your official finish time.

What is a good Ironman finish time for an age-grouper?

Average age-group athletes typically finish between 11 and 14 hours. Sub-12 hours is considered a strong performance for recreational triathletes, while elite age-groupers can finish under 9–10 hours. First-timers completing within the 17-hour cutoff should be proud of the achievement.

How do I calculate my swim pace for the Ironman?

Your swim pace is expressed as the time it takes you to cover 100 metres. In a pool or open-water session, swim a set distance at race effort and divide total time by the number of 100m lengths. Most Ironman-capable swimmers hold a pace between 1:30 and 2:30 per 100m.

What percentage of FTP should I target for the Ironman bike leg?

For a full 180 km Ironman bike, most coaches recommend riding at 65–72% of your Functional Threshold Power (FTP). Going too hard early — above 75% FTP — typically leads to a significant run performance drop. Conservative pacing on the bike almost always pays off in the marathon.

What is the 'Quarters Pacing Strategy' for an Ironman?

The Quarters Strategy splits the marathon into four roughly equal 10 km segments. Many athletes recommend keeping the first two quarters conservative (slower than goal pace), picking up effort in the third, and leaving everything on the course in the final quarter. This prevents blowing up early in the run.

How much time should I budget for transitions in an Ironman?

Transition times vary by experience and race venue layout. T1 (swim-to-bike) typically takes 3–10 minutes, and T2 (bike-to-run) 2–7 minutes. First-timers should budget 5–8 minutes for each. Practiced athletes and those targeting podium positions often get under 3 minutes per transition.

Should I train at race pace before an Ironman?

Yes — incorporating race-pace efforts into your training is essential for teaching your body the specific demands of Ironman effort. This means long bike rides at your target Ironman power, long runs at your target marathon pace, and open-water swims at race pace. Doing so in training removes the guesswork on race day.

How does the Ironman Pacing Calculator estimate my bike power?

This calculator estimates your FTP from your 20-minute average power test result (multiplying by 0.95), then applies a percentage of that FTP based on your chosen race strategy — conservative (55–60%), moderate (65–70%), or aggressive (72–76%). The output gives you a recommended wattage range to hold on the 180 km bike leg.

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