Learn the game
How ratings work
Your rating says how strong you are against real people. It changes only in rated online matches, with the FIBS formula backgammon players have used for decades.
On this page
01The basics
- Everyone starts at 1500.
- Beat a stronger player and you gain more; lose to a weaker one and you lose more.
- Longer matches count more, because skill shows more over more games.
- New players move faster until their rating settles.
02Rating calculator
See what a rated match would do to your rating before you play it.
Match length (points)
Your experience
Your chance to win
43.6%
- If you win
- +25.0
- If you lose
- −19.3
Includes your new-player boost: changes are multiplied by 4.95 at this experience.
03The formula
For a match to N points between you (rating A) and your opponent (rating B):
Your chance to win
P = 1 − 1 / (10^((A − B) × √N / 2000) + 1)
Match value
V = 4 × √N
You win: you gain
+ V × (1 − P)
You lose: you lose
− V × P
An even match to 5 between equal players moves each rating by about 4.5 points. An upset moves more, a win you were expected to get moves less.
04Experience and new players
Your experience is the total length of your rated matches: a match to 5 adds 5. Until it reaches 400, your changes are multiplied, by almost 5 at the start and falling steadily to 1 at 400, so a new player reaches their real level in a few dozen matches.
Below 50 experience your rating is provisional and shows a small mark next to it.
05Getting on the leaderboard
The rating leaderboard lists real people only, and only once their rating means something:
- A verified email and a display name you chose.
- At least 20 experience in rated matches.
06Fair play
Only the first 3 rated matches between the same two players in 24 hours change their ratings. Later ones are still played, recorded and count for XP, so nobody can farm points from a friend.
Questions
Why did my rating move so much in my first matches?
New players get a boost of up to 5 times the normal change, shrinking as your experience grows to 400. It gets you to your real level quickly.
What does the small mark next to my rating mean?
Your rating is still provisional: you have less than 50 experience. It disappears on its own as you play more rated matches.
Do games against the AI count?
No. Only rated matches against people change your rating. AI games earn XP, streak days and World Tour stars.
What is a good rating?
1500 is where everyone starts. For a sense of scale, the AI levels play at roughly 1100 (Novice), 1550 (Intermediate), 1850 (Expert) and 2000 (Grandmaster).
Put a number on your game
Play rated matches online and watch your rating settle. The leaderboard lists humans only.