Long-course race safety
Ironman Cutoff Calculator
Check whether your full Ironman or 70.3 race plan clears the swim, bike, and finish cutoffs with enough buffer to stay calm late in the day.
Swim pace / 100m
Run pace / km
Cutoff safe
48m
Smallest buffer at swim.
Swim
Clock 01:31:50
48m
buffer
Bike
Clock 09:00:39
1h 29m
buffer
Finish
Clock 14:24:07
2h 35m
buffer
Edit official cutoffs
Use the defaults for planning, then replace these with your race athlete-guide times. Some venues use different intermediate rules or course-closure clocks.
What the result means
The swim checkpoint compares your swim split plus wave offset against the swim cutoff. The bike checkpoint compares swim + T1 + bike against the cumulative bike cutoff. The finish checkpoint compares the full day against the final cutoff.
Green buffers are planning room, not permission to ignore race rules. Always check the official athlete guide because IRONMAN rules state that venue-specific guides provide cutoff details and exceptions.
- Official event guides can vary by venue, wave, weather, road closure, and race director instruction.
How to read cutoff buffer
Green does not mean careless. A useful long-course plan keeps buffer at the swim exit, bike cutoff, and finish line because small delays stack up: crowds, bathroom stops, bottle drops, hot run pacing, or a slow transition can all spend minutes.
- Check swim, bike, and finish clocks separately.
- Use wave offset only when it matches your event's cutoff rules.
- Recalculate after changing bike effort or run pace.
Example race read
A full-distance athlete projecting a 1:35 swim, 7:10 bike including T1, and 5:25 marathon may look safe overall, but the bike cutoff can still be the pressure point if the course closes at a fixed clock time.
Common mistakes
The most common mistake is judging only the final 17-hour or 8:30 clock. Cutoff risk often appears earlier on the swim or bike, especially when a nervous swim, long T1, headwind, or mechanical delay removes the buffer before the run begins.
Use official race-guide times
The calculator starts with common planning defaults, but it is deliberately editable. IRONMAN's competition rules say event-specific athlete information guides provide cutoff guidance and exceptions, so the trusted workflow is: open your event guide, copy the swim, bike, and finish cutoffs, then check your buffer here.
Next planning step
If your cutoff buffer is tight, do not guess. Build a more conservative full race plan, then check bike power, run durability, and fueling separately.
Trust and methodology
How this page should be used
Last updated
July 13, 2026
Maintained by
M Imtinan Farooq
Status
Planning estimate, not a race guarantee
Formula summary
Checkpoint buffer = official cutoff clock minus projected checkpoint clock.
Key assumptions
Entered paces, transitions, wave offset, and cutoff fields match the athlete guide.
Limitations
Venue-specific athlete guides and race-day officials override planning defaults.