The ELO rating system is a method for calculating the relative skill of players in competitive games. Originally developed by physicist Arpad Elo for chess in the 1960s, it's now used everywhere — from FIFA world rankings to online gaming to competitive apps like Tactiko.
Every player starts with a base rating (typically 1200). When you win, your rating goes up. When you lose, it goes down. The amount it changes depends on the strength of your opponent — beat a stronger player and you gain more points. Lose to a weaker one and you drop further.
Before each match, the system calculates the expected outcome based on both players' ratings. If a 1400-rated player faces a 1200-rated player, the system expects the stronger player to win about 76% of the time.
The formula for expected score:
After the match, your rating changes based on how the actual result compares to the expected result:
Where K is the “K-factor” — a number that controls how much each match affects your rating. A higher K means bigger swings. In Tactiko, K = 30, meaning you can gain or lose up to 30 points per match.
The K-factor determines how reactive the rating system is. Different systems use different values:
Tactiko uses K = 30 for all players regardless of experience. This means every match has a meaningful impact on your ranking — a single win can move you up 15-30 points, and a loss drops you by the same amount.
The beauty of ELO is that it's self-correcting. If you're underrated, you'll beat players at your rating level and climb quickly. If you're overrated, you'll lose and drop until you reach your true skill level. Over time, every player converges to a rating that accurately reflects their ability.
It also handles different opponents naturally. You don't need to play every other player to be ranked — the system infers your skill from who you beat and who beats you. A 1400-rated player who only plays other 1400s is considered the same strength as a 1400 who plays a wider range of opponents.
In Tactiko, every ranked match (League and Cup) affects your ELO. You start at 1200 and your rating adjusts after every match based on the result and your opponent's strength. You can see your current ELO on the home screen, track it over time on your team page, and compare it on the leaderboard.
Bots also have ELO ratings. They play matches against each other and against humans, so their ratings reflect how well they perform. The strongest AI bots can reach ratings above 1400 — can you beat them?