UK Ultra Race Planner · Independent planning tool by ULTRALABS
Arc of Attrition 100
Arc 100M by UTMB, the 100-mile race. Not the Arc 100K, 50K or 20K.. Organiser: Arc of Attrition by UTMB.
2027 edition (22 January 2027, Coverack to Perranporth), provisional table · Partially verified · race data 2026-09-09
Partially verified: plan with care, some fields are provisional or secondary. New finish at Perranporth Airfield, 173 km and 37 hours. The organiser's page already shows nine aid stations with cut-off times, but the Runner's Guide is not out, wave times are TBC and the page's date fields still say 2026. Plan with it, and re-check everything when the Runner's Guide appears.
Start to finish, including every stop and any sleep. Limit 37 h 30 min.
Enter a target finish time to see your schedule.
The checkpoint list below shows the official distances, cut-offs and access rules for 2027 edition (22 January 2027, Coverack to Perranporth), provisional table without a plan.
| Checkpoint | Distance | Section | Arrive | Stop | Depart | Cut-off | Buffer |
|---|---|---|---|---|---|---|---|
Coverack (start) startcrew prohibited Rules and notes
| 0.0 mi | Start | – | – | – | none published | – |
AS1 Lizard Point aid · timingcrew prohibited Rules and notes
| 10.7 mi +10.7 mi | – | – | min | – | 2027-01-22 16:30 must have left by | – |
AS2 Porthleven aid · timing · crew pointcrew allowed Rules and notes
| 25.1 mi +14.4 mi | – | – | min | – | 2027-01-22 20:30 must have left by | – |
AS3 Penzance aid · timing · rest areacrew prohibited Rules and notes
| 40.3 mi +15.2 mi | – | – | min | – | 2027-01-23 01:00 must have left by | – |
AS4 Porthcurno aid · timingcrew prohibited Rules and notes
| 51.4 mi +11.1 mi | – | – | min | – | none published | – |
AS5 Land's End aid · timing · crew point · drop bag · rest areacrew allowed Rules and notes
| 56.1 mi +4.7 mi | – | – | min | – | 2027-01-23 07:00 must have left by | – |
AS6 Pendeen aid · timingcrew prohibited Rules and notes
| 66.2 mi +10.1 mi | – | – | min | – | 2027-01-23 11:00 must have left by | – |
AS7 Lelant aid · timing · crew pointcrew allowed Rules and notes
| 83.8 mi +17.5 mi | – | – | min | – | 2027-01-23 18:00 must have left by | – |
AS8 Godrevy aid · timingcrew prohibited Rules and notes
| 90.3 mi +6.6 mi | – | – | min | – | 2027-01-23 20:00 must have left by | – |
AS9 Portreath aid · timing · crew pointcrew allowed Rules and notes
| 97.7 mi +7.3 mi | – | – | min | – | 2027-01-23 23:30 must have left by | – |
Perranporth Airfield (finish) finish · timing · rest area · drop bagcrew unknown Rules and notes
| 107.6 mi +9.9 mi | – | – | – | – | 2027-01-24 02:30 must arrive by | – |
Times are Europe/London local time, with the day. Distances are the organiser’s cumulative figures converted to miles. Buffer is the cut-off minus your planned arrival or departure, whichever the organiser’s rule applies to. A missed cut-off is shown even when the finish is inside its limit. Colour is never the only signal; every status carries a word.
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How this works
Method, assumptions and sources
Time budget. Your target is elapsed time from the start to the finish line. Every stop you enter, sleep included, is subtracted first; what is left is the moving budget. If the stops use up the target the tool says so rather than squeezing the moving time.
Sections. In “share the target” mode the moving budget is split across sections in proportion to their distance, so every section is at the same average speed. That is arithmetic, not a model of climbs, mud or night. Lock a section to a time you trust, or give it a factor (1.3 means you expect it to take 30% longer per mile than the rest), and the remainder is shared across the others. In “enter section times” mode your times decide the finish and the target is only compared.
Cut-offs. Each rule is compared against the instant it applies to. A departure rule is checked against your departure, so a stop can turn a cleared arrival into a missed cut-off. Where the organiser publishes a time without saying whether it is for arriving or leaving, the comparison is against departure and marked provisional. Exactly on the limit is judged by the organiser’s stated rule, or flagged when there is none. No cut-off in the table does not mean no limit.
Seconds. Everything is calculated in whole seconds and the total is conserved exactly; displayed minutes are rounded afterwards and never feed back into the comparison.
Scenarios. Changes are to section duration or stop length. Keep-finish scenarios reallocate the reduced moving budget; keep-moving scenarios push later times back with no renormalisation.
Verification is not accuracy. A verified checkpoint table tells you the rules are right. It says nothing about whether the constant-speed split matches how you will actually move.
Official sources for 2027 edition (22 January 2027, Coverack to Perranporth), provisional table
- Arc 100M by UTMB (race page, embedded checkpoint table) · verified, edition 2027, accessed 2026-09-09 · Time charts / track points · Page is noindex; cut-off datetime fields carry 2026 dates while labels read Fri/Sat/Sun times. Treated as provisional.
- Regulations, Arc of Attrition by UTMB · verified, edition 2027, accessed 2026-09-09 · Sections 3 and 4: personal assistance; time barriers
- FAQs, Arc of Attrition · verified, edition 2027, accessed 2026-09-09 · Crew-station list uses 2026 km values; subject to change.
- Event Schedule 2027 · verified, edition 2027, accessed 2026-09-09 · Arc 100M start 13:00 Coverack; course close TBC.
Not verified for this edition
- wave start times (the schedule says wave starts from 13:00; cut-offs are calculated from the last wave)
- the finish cut-off: the page header says 37 hours and ends at 02:00 Sunday (13:00 plus 37 h), while the table label reads 02:30 Sunday, which is 37 h from a 13:30 last wave as the regulations require and matches the page's Coverack row (fastest 13:00, slowest 13:30); 02:30 is used, so a 13:00 starter has 37.5 h on the clock
- the cut-off table's machine-readable dates still carry 2026, so the table may be a draft
- Porthcurno (AS4) has no published cut-off
- the 2027 Runner's Guide is not published; the regulations carry a kit section and the FAQ bans spectating at the start, but the linked kit PDF is still headed 2026
Amendments and conflicts recorded
- Finish moved from Porthtowan Eco Park (2026) to Perranporth Airfield; route 161.9 km to 173 km; limit 36 to 37 hours.
Race data version 2026-09-09. Independent planning tool by ULTRALABS; not affiliated with the organiser. The organiser’s own documents are the authority and change between editions.