Plan your duathlon race with precision. Enter your Run 1 distance and pace, Bike distance and speed, Run 2 distance and pace, plus your T1 and T2 transition times — and get back a full segment-by-segment time breakdown with cumulative splits and your total finish time.
Total Finish Time
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Run 1 Time
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Transition 1 (T1)
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Bike Time
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Transition 2 (T2)
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Run 2 Time
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Total Distance
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A duathlon is a multisport endurance race consisting of three segments: run, bike, then run again (run-bike-run). Unlike a triathlon, there is no swimming leg. Events range from super sprint distances to long-course races covering over 190km of total distance.
Enter your target pace for each run segment (in minutes and seconds per km), your average bike speed (in km/h), and your estimated transition times for T1 and T2. The calculator computes the duration of each segment, adds them together, and gives you a predicted total finish time along with cumulative split times.
T1 is the first transition — the time you spend moving from Run 1 to the bike (changing footwear, putting on a helmet, etc.). T2 is the second transition — moving from the bike back to running (racking the bike, swapping helmet for a cap, etc.). Both transitions count toward your official race time, so practicing them matters.
Common duathlon formats include: Super Sprint (2.5km / 10km / 2.5km), Sprint (5km / 20km / 2.5km), Standard/Olympic (10km / 40km / 5km), Middle (10km / 60km / 10km), and Long Distance (10km / 150km / 30km). Many local events also use custom distances.
Most duathletes run slightly slower in Run 2 due to accumulated fatigue from the bike leg — this is sometimes called 'brick legs'. A conservative approach is to target Run 2 pace roughly 10–30 seconds per km slower than Run 1. With experience and brick training, you can narrow this gap significantly.
Enter your realistic average moving speed on the bike, accounting for hills, terrain, and wind. Beginners typically average 25–30 km/h, intermediate cyclists 30–35 km/h, and experienced competitors 35–45 km/h on flat courses. Avoid using peak speed — average speed gives the most accurate time estimate.
This calculator is specifically designed for run-bike-run duathlon events. For triathlon pacing (swim-bike-run), you would need a triathlon-specific calculator. However, you can use the bike and run sections as a rough planning tool for any individual segment.
Focus on three areas: brick training (back-to-back bike-to-run sessions to reduce Run 2 fatigue), transition practice (smooth, fast T1 and T2 can save 30–90 seconds), and pacing discipline on the bike (going too hard on the bike destroys Run 2). Consistent aerobic base training across all three disciplines is key.