About races.fyi
races.fyi exists to answer one question with data instead of forum threads: which marathon should you run, and what should you expect on race day?
Where the data comes from
Every figure on this site is compiled by hand from public sources: official race websites and course maps, published results and finisher counts, historical weather records for each race's city and date, and course-certification data. We currently cover 43 marathons.
Numbers are deliberately rounded. Elevation gain varies by measurement method (GPS traces routinely disagree with certified course maps by 10–20%), weather medians summarise decades of variance into one number, and finisher counts move year to year. Treat our figures as honest orientation, not gospel — and always confirm entry details with the race organiser before booking anything.
How the PR score works
The PR score (1–10) is our editorial rating of how likely a well-trained runner is to set a personal best on a given course. It weighs four things: the elevation profile (total climbing and where it falls in the race), the historical weather odds for the race date, the course layout (corners, cobbles, congestion, altitude), and how well the race is organised for time-chasing (pacers, corrals, a competitive field around you).
It is deliberately opinionated. Berlin and Valencia earn 10s because everything aligns; New York earns a 4 not because it's a bad race — it's one of the best — but because five bridges and a rolling finish are honest facts about your finishing time.
How the pacing plans are built
Our pacing plans start from even splits for your goal time, then redistribute effort across hand-mapped course segments — downhill starts, mid-race climbs, exposed late miles — the way experienced runners actually race them. The redistribution is normalised so the splits always sum exactly to your goal time. They are guidance for a well-executed race, not a physiological prescription: on hot days or windy days, effort beats any split table.
Boston qualifying data
Qualifying standards belong to the Boston Athletic Association and change over time. We state the year each table applies to and update when the B.A.A. announces changes, but you should verify against baa.org before planning a season around a number. Cutoff buffers cited on our BQ pages are based on recently published acceptance cutoffs.
Corrections
Spotted a number that's off? We'd genuinely like to know — accuracy is the entire point of this site. Course details change, races reroute, and fields grow; if something here lags reality, it gets fixed.