Race statistics
DNF Rates: The 30 Toughest Races to Finish
DNF rate is the percentage of starters who did not finish, using only participants recorded as finished or DNF. Only races with at least 50 recorded starters are included, so the rates below are statistically meaningful.
| # | Race | Location | Distance | Starters | DNF Rate |
|---|---|---|---|---|---|
| 1 | UTS 165 | - | - | 92 | 65% |
| 2 | 13 Valleys Ultra | - | - | 192 | 59% |
| 3 | Dragon's Back Race | Wales, United Kingdom | 380km | 1,411 | 55% |
| 4 | Conwy Half Marathon | Conwy, United Kingdom | 21.1km | 6,156 | 55% |
| 5 | C2C in a Day | - | - | 1,927 | 52% |
| 6 | Devon Coast to Coast | - | - | 52 | 50% |
| 7 | Cape Wrath Ultra | - | - | 1,149 | 48% |
| 8 | Pilgrims Ultra - 100 Mile | - | 160.9km | 76 | 47% |
| 9 | Hardmoors 110 | - | 173.6km | 214 | 47% |
| 10 | Montane Spine Challenger South - Summer Edition | High Peak, United Kingdom | 174.32km | 313 | 46% |
| 11 | Montane Spine - Summer Edition | - | - | 1,010 | 46% |
| 12 | Summer Spine | - | - | 91 | 46% |
| 13 | Hardmoors 160 | - | 247.65km | 339 | 44% |
| 14 | Salomon Ben Nevis Ultra | - | - | 229 | 44% |
| 15 | UTS 100 | - | - | 181 | 43% |
| 16 | Summer Spine Challenger Race | - | - | 111 | 39% |
| 17 | Lakeland 100 | Coniston, United Kingdom | 168.89km | 2,597 | 37% |
| 18 | 100 km Pilgrims Ultra | Holy Island, United Kingdom | 99.91km | 69 | 36% |
| 19 | Montane Spine Challenger North - Summer Edition | Hawes, United Kingdom | 242.57km | 118 | 36% |
| 20 | Hardmoors 60 | Guisborough, United Kingdom | 100.58km | 359 | 35% |
| 21 | The Fellsman | - | - | 204 | 34% |
| 22 | Ultra Trail Snowdonia 100km | Snowdon, United Kingdom | 100km | 1,189 | 33% |
| 23 | Montane Summer Spine | Edale, England | 431.304km | 480 | 33% |
| 24 | Saint Cuthbert's Way 100 KM | - | 100km | 421 | 31% |
| 25 | Ridgeway Challenge | Ivinghoe Aston, United Kingdom | 139.9km | 120 | 30% |
| 26 | Ultra Great Britain | - | - | 63 | 29% |
| 27 | LAW 75 | - | - | 172 | 28% |
| 28 | Wales Ultra Trail | - | - | 169 | 28% |
| 29 | Pennine Journey North Ultra | - | - | 86 | 27% |
| 30 | Salomon Glen Coe Skyline | - | - | 540 | 26% |