How hard is the course. How deep is the field.
The Kenyan Running Difficulty Index rates how the course actually runs. The Kenyan Running Elite Field Index rates how deep the field around you is. Both 1 to 10. The methodology is public. Inputs are traceable to primary sources where they exist.
Updated Oct 17, 2026 · 12 races
By Difficulty
How the course actually runs. Elevation, weather, and the tactical brutality of where the field blows up.
- 1Boston Marathon10.0
- 2NYC Marathon9.2
- 3Honolulu Marathon7.4
- 4LA Marathon5.4
- 5London Marathon3.9
- 6Chicago Marathon2.6
- 7Tokyo Marathon2.4
- 8CIM Marathon2.4
- 9Dubai Marathon1.5
- 10Valencia Marathon1.4
- 11Amsterdam Marathon1.2
- 12Berlin Marathon1.0
By Elite Field
How deep the elite field around you is. Prize purse, time bonuses, elite participation, record-attempt potential.
- 1Berlin Marathon9.5
- 2Boston Marathon9.5
- 3London Marathon9.5
- 4NYC Marathon9.0
- 5Chicago Marathon9.0
- 6Valencia Marathon8.5
- 7Tokyo Marathon8.0
- 8Dubai Marathon7.0
- 9Amsterdam Marathon6.5
- 10Honolulu Marathon3.8
- 11LA Marathon3.5
- 12CIM Marathon2.5
All 12 races
Six World Marathon Majors, three Kenyan-favored international fast courses (Dubai, Valencia, Amsterdam), three US-market anchor races (CIM, LA, Honolulu). Click any race for the full breakdown.
NYC Marathon
New York, USA
Five major bridges and a punishing late-stage 5th Avenue climb make New York City the tactically most-unforgiving of the World Marathon Majors despite a moderate elevation profile.
Read the full breakdown →Oct 10, 2027Chicago Marathon
Chicago, USA
Exceptionally flat through 29 neighborhoods. Tied with Berlin as the marathon course with the most world records in the modern era. Two recent world records: Kelvin Kiptum's 2:00:35 (2023) and Ruth Chepngetich's 2:09:56 (2024).
Read the full breakdown →Sep 26, 2027Berlin Marathon
Berlin, Germany
Hosts more world record performances than any other marathon course in the modern era. The flat profile, cool autumn temperatures, and dense pacing infrastructure make Berlin the venue where well-trained amateurs most often produce their fastest legal time.
Read the full breakdown →Apr 19, 2027Boston Marathon
Boston, USA
Unidirectional point-to-point with severe net negative elevation drop. The first half's 1,275ft descent destroys quadriceps via eccentric loading; the Newton Hills at miles 16-21, including Heartbreak Hill, arrive precisely when glycogen is depleted.
Read the full breakdown →Apr 24–25, 2027London Marathon
London, UK
Site of the first sub-2-hour marathon in a record-eligible race in history (Sabastian Sawe, 1:59:30 at the 2026 edition); the same race produced Tigst Assefa's 2:15:41, the women-only world record. The flat profile is conducive to records, but London also carries one of the deepest recreational fields in the sport, with a heavy charity-runner share that pulls the average finish time long compared to faster-course WMMs.
Read the full breakdown →Mar 7, 2027Tokyo Marathon
Tokyo, Japan
Technical flatness: no major climbs but constant micro-undulations and sharp urban turns prevent settling into monotonous cadence.
Read the full breakdown →Jan 17, 2027Dubai Marathon
Dubai, UAE
Sea-level, uniformly flat geometry with exceptionally wide roads. The most Ethiopian-dominated race on the global elite calendar: all 20 winners (men and women combined) across the last 10 editions are East African, 19 of them Ethiopian. Historically offered up to $1,000,000 for a world record (most prominently in 2008); the current published prize structure does not list a WR bonus.
Read the full breakdown →Dec 6, 2026Valencia Marathon
Valencia, Spain
Offers the biggest single performance bonus in the sport: €1,000,000 for a world record. Exceptionally flat layout attracting phenomenally deep elite fields. Course record dropped consecutively in 2020, 2022, 2023.
Read the full breakdown →Oct 18, 2026 · results being addedAmsterdam Marathon
Amsterdam, Netherlands
Extreme geographical flatness combined with historically stable fall weather (minimal wind) make it a frequent personal-best venue. Like Dubai, Amsterdam shows 100% East African winner representation across the last 10 editions (mixed Kenyan and Ethiopian, unlike Dubai's near-total Ethiopian dominance). Course record has progressively dropped 2016-2025.
Read the full breakdown →Dec 6, 2026CIM Marathon
Sacramento, USA
One of the top Boston Qualifier routes in the US, with a high concentration of Olympic Trials Qualifiers. The sweeping, gently rolling net-downhill terrain and minimal turns make it BQ-friendly. Net drop of 366ft complies with Boston's index rules (which penalize >1,500ft drops from 2027).
Read the full breakdown →Dec 13, 2026Honolulu Marathon
Honolulu, USA (Hawaii)
No time limit, no qualifying requirement, no field cap. Among major marathons, uniquely positioned for recreational/destination running. Heat ceiling (high humidity + tropical conditions) is the dominant performance limiter, not elevation.
Read the full breakdown →Mar 7, 2027LA Marathon
Los Angeles, USA
The 'Morgan & Morgan Marathon Chase': elite women start 15-18 minutes before elite men; first runner to cross the finish line claims a $10,000 bonus. Drives unusual late-race tactical pursuits.
Read the full breakdown →How the scores work
The Kenyan Running Difficulty Index combines four weighted factors: Topographic Stress (30%), Atmospheric Stress (20%), Course Friction (15%), and Tactical Brutality (35%). The heaviest weight is on Tactical Brutality. That is what a Kenyan coach watches first: where the field actually blows up.
The Kenyan Running Elite Field Index tracks prize purse, time-bonus structure, course-record incentives, the density of top-tier elite finishers (Kenyan, Ethiopian, Eritrean, and other dominant nationalities) in recent editions, and the course's suitability for record attempts. The field around you changes the texture of a race independent of how hard the course is.
Both scores are derived from publicly available data: race websites, World Athletics results, weather archives, and elevation surveys. The methodology is published and the inputs are traceable. Most race pages cite primary sources alongside the score; pages still at preliminary confidence are flagged on the page itself. The 1-10 range is a presentation choice; raw subscores remain the canonical input and the most extreme courses are clamped to the endpoints.
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