# How is rating score calculated on Lichess?

I've recently lost to a 1500 player. My rating is about 1200. Ironically, he got 163 points. How is it possible for a 1500 player to gain more points on a lower-rated player? The system that Lichess uses to calculate rating scores is very confusing. How is it done?

Without the link to player profiles and the game iteself, it is difficult to say for certain exactly what happened.

For one, Lichess starts new users with a rating of 1500.[1]

Even if your opponent didn't have a 1500 rating, as double-beep points out Lichess uses the Glicko-2 rating system[2] which explicitly tracks the player's rating, a rating deviation, and a rating volatility. The system views a player's rating from a stochastic perspective, as an interval not a single point value.[1]

The system will detect and provide a larger rating change in various circumstances including:

• "exceptionally strong results after period of stability",[3] or
• after a period of inactivity (it is less certain if rating is still accurate).

The Glicko-2 creator, Dr. Mark Glickman, provides the mathematical formulas for the system.[3,4]

As an example, consider this classical game on Lichess. At the time of the game, the player with the White pieces had only played 1 rapid game. The system seeded the player (White) with a 1500 rating but annotated it as 1500? to denote the provisional rating.

References:
[1] Chess Rating Systems, Lichess website.
[2] What rating system does Lichess use?, Lichess FAQ page.
[3] Example of the Glicko-2 System, ME Glickman, 30 Nov 2013.
[4] http://www.glicko.net/glicko.html, website by Mark E. Glickman.