How Ratings Work
We use the Glicko-2 rating system — it tracks not just your rating but how sure it is about it — plus a giant-killer bonus that rewards big upsets.
Rating, uncertainty & volatility
Classic Elo only knows your number. Glicko-2 also tracks a rating deviation (RD) — how confident it is that the number is right — and a volatility that measures how erratic your recent results have been.
New players start at 1000 with a high RD of 225. Because the system is unsure where you belong, your first handful of games swing your rating a lot — that's the placement period. As you play, RD shrinks and your rating settles, so each later game nudges it less. This is why a chess.com newcomer can jump 150+ points from a single upset, while a veteran barely moves.
The giant-killer bonus
On top of the Glicko result, beating a much higher-rated opponent earns a bonus — a one-sided reward that adds points to the pool (your opponent isn't docked extra). It kicks in once the gap is at least 100 points:
- ·+10% of your gain per 100 points of rating gap. Beat someone 300 above you and your gain is boosted by 30%.
- ·A draw against a giant earns half that bonus.
- ·The bonus tapers with your own rating — full strength at 500 and below, fading linearly to zero at 1500. It's a leg up for newcomers and a non-factor once you're established.
taper = clamp((1500 − yourRating) ÷ 1000, 0, 1) · draw counts as half
Worked examples
Calculated live by the same engine that runs the leaderboard.
Placement — a brand-new player wins
Win vs even opponentYour first games carry huge uncertainty (RD 225), so the system moves you a long way to find your level quickly.
Giant-killer — beating someone well above you
Win vs +400An established player (RD ~60) topples an opponent 400 points higher. The base Glicko gain is boosted by the one-sided giant-killer bonus.
Holding a giant to a draw
Draw vs +400A draw against a much stronger player is still an achievement — it earns half the giant-killer bonus a win would.
Up top, the bonus fades out
Win vs +400The giant-killer bonus tapers to zero by 1500. A strong player beating an even stronger one gets the plain Glicko result — no bonus.