Credits, sources and method

Data sources

  • The Fjelstul World Cup Database by Joshua C. Fjelstul, Ph.D. Licensed under CC BY-SA 4.0. Source: github.com/jfjelstul/worldcup. Used for squads, goals, appearances, awards, coaches, qualified teams, host countries and stadiums for every men's and women's World Cup.
  • OpenFootball football.json, released into the public domain (CC0). Source: github.com/openfootball/football.json. Used for league seasons and Champions League participants from 2010/11 onwards; final tables are computed from match results.

Footbillion adapted these datasets: we combined tables, grouped club name variants, added nicknames and spelling aliases, removed small lists and calculated values. Any errors introduced in that process are ours.

The Footbillion question bank

The bank currently holds 1,393 prompts (867 about World Cup players, 339 about clubs and 187 about countries, coaches and host cities) drawing on 10,401 players, 314 clubs, 88 national teams, 475 coaches and 202 host cities. It is generated by tools/build-bank.py from pinned commits of both sources, so the same input always produces the same bank.

Because it is adapted from a CC BY-SA 4.0 database, the bank is released under the same CC BY-SA 4.0 licence. You can download it at /assets/bank.json; please credit "Footbillion, adapted from the Fjelstul World Cup Database and OpenFootball".

How answer values are calculated

  1. Fame score. Each possible answer gets a score from public facts. Players: 5 points per World Cup attended, 2 per match played (match data starts in 1970), 6 per goal, 12 per tournament award, 8 per World Cup final appearance and 10 per goal in a final, plus a small bump for forwards and a short hand-picked list of household names. Clubs: 3 points per top-flight season in the data, 6 per Champions League season, 12 per league title and a bonus for high finishes. Countries: World Cup appearances, matches and titles. Coaches: tournaments, matches and titles. Host cities: World Cup matches hosted.
  2. Rank. Inside each prompt, answers are sorted from most to least famous. Ties share a rank.
  3. Price. The rank is turned into a percentile p from 0 (most famous) to 1 (least famous), and the value is £10m + £5m × round(28 × p). That gives £10m for the obvious pick and £150m for the deepest cut.

These are estimates of familiarity, not live player statistics or opinion polls.

Disclaimer

Footbillion is an independent fan game, not affiliated with Krillion, Footillion, Goalillion, FIFA or any club, league or federation. All trademarks belong to their owners and are used only to describe historical football facts.

Code and design

The game code, visual design, copy and scoring were written for Footbillion. No code, text or artwork was copied from other games.

Last updated 2026-11-13.