Key Takeaways
- Bike typically accounts for 50-55% of total race time
- Transition times can add 5-10 minutes - practice makes perfect
- Run pace is usually 15-30 seconds slower per km after biking
- Sprint triathlons are great for beginners - finish times average 1:00-1:30
- Ironman cutoff is 17 hours - most finishers complete in 12-15 hours
What Is a Triathlon? Understanding the Three-Sport Challenge
A triathlon is an endurance multisport race consisting of swimming, cycling, and running over various distances. Athletes compete for fastest overall completion time, including transitions between disciplines. The sport tests all-around fitness and strategic pacing.
Triathlons originated in the early 1970s in San Diego, California, and have grown into a global phenomenon. The Ironman triathlon, first held in Hawaii in 1978, remains the most prestigious endurance event, challenging athletes to complete 140.6 miles (226 km) in a single day.
Triathlon Distances Explained
| Distance | Swim | Bike | Run | Total | Typical Time |
|---|---|---|---|---|---|
| Super Sprint | 400m | 10km | 2.5km | ~13km | 30-60 min |
| Sprint | 750m | 20km | 5km | ~26km | 1:00-1:30 |
| Olympic | 1.5km | 40km | 10km | 51.5km | 2:00-3:30 |
| Half Ironman (70.3) | 1.9km | 90km | 21.1km | 113km | 4:30-7:00 |
| Full Ironman (140.6) | 3.8km | 180km | 42.2km | 226km | 8:00-17:00 |
How This Triathlon Time Predictor Works
Our calculator uses your individual discipline paces and transition estimates to provide an accurate finish time prediction:
Swim Calculation
Enter your pace per 100 meters. For example, if you swim 100m in 2:00, enter 2 minutes and 0 seconds. The calculator multiplies this by the race distance (7.5x for Sprint's 750m, 15x for Olympic's 1500m, etc.).
Bike Calculation
Enter your average cycling speed in km/h. The calculator divides the course distance by your speed. Remember to account for hills, wind, and draft-legal vs. non-drafting conditions.
Run Calculation
Enter your per-kilometer pace. Important: Your triathlon run pace will likely be 15-45 seconds slower than a standalone race due to accumulated fatigue from swimming and biking.
Pro Tip: The Brick Effect
When transitioning from bike to run, your legs feel heavy and awkward - this is called the "brick" sensation. Train with brick workouts (bike immediately followed by a run) to adapt to this feeling and get a more realistic estimate of your race-day run pace.
Mastering Transitions (T1 and T2)
Transitions are often called the "fourth discipline" of triathlon. Efficient transitions can save you 2-5 minutes compared to a disorganized approach.
T1 (Swim to Bike) Tips:
- Practice removing your wetsuit while moving to your bike
- Use elastic laces so you don't have to tie shoes
- Apply sunscreen before the race (no time in T1)
- Keep helmet unbuckled and upside-down on aerobars
- Target time: 2-4 minutes for beginners, under 90 seconds for pros
T2 (Bike to Run) Tips:
- Dismount before the line and run with your bike
- Pre-position your running shoes with elastic laces
- Have race belt with bib ready to clip on
- Grab nutrition for the run if needed
- Target time: 1-2 minutes for beginners, under 45 seconds for pros
Race Day Pacing Strategy
Swim Pacing
Start conservatively to avoid oxygen debt. The first 200m sets the tone - go out too hard and you'll struggle to recover. Sight frequently in open water to avoid swimming extra distance.
Bike Pacing
The bike leg is where races are won or lost. Push too hard and your run will suffer. Aim for a perceived effort of 7/10 for sprint distance, 6/10 for Olympic and longer. Use power or heart rate if available.
Run Pacing
Negative split if possible - start slower than goal pace for the first kilometer as your legs adjust. The bike-to-run transition is when most athletes fade due to going out too fast.
Frequently Asked Questions
This calculator is highly accurate when you input realistic training paces. However, race-day conditions like weather, course terrain, nutrition, and adrenaline can cause variations of 5-15%. Use your training data for the most reliable prediction.
Use your sustainable training pace, not your race pace from single-sport events. Your triathlon run will be slower than a standalone 5k due to prior fatigue. For the bike, use your average speed from long rides, not short sprints.
For a Sprint triathlon, 1:15-1:45 is typical for beginners. Olympic distance beginners finish in 2:30-3:30. The most important thing is finishing! Focus on completing the race comfortably before worrying about time.
Beginners typically take 3-5 minutes per transition. With practice, aim for under 2 minutes each. Elite athletes complete T1 in under 60 seconds and T2 in under 30 seconds. Practice your transitions during training!
Full Ironman has a 17-hour cutoff. Intermediate cutoffs are: Swim 2:20, Bike 10:30 (from race start), Run 17:00 (from race start). Half Ironman (70.3) typically has an 8:30 cutoff with a 1:10 swim cutoff.
The bike offers the most time savings since it's 50-55% of total race time. A 1 km/h increase in bike speed can save 20-40 minutes in an Ironman. However, improving your weakness often yields the biggest gains. If swimming takes 30% of your race time, it's worth addressing.