Free chess calculator
Glicko-2 rating calculator
Elo tells you a number; Glicko-2 also tells you how sure it is. Set your rating, its deviation and volatility, add a period of games, and see all three update at once.
How unsure the system is about you. 350 is a brand-new player; established players sit near 50.
How erratic your recent results have been. 0.06 is a typical default.
Glicko-2 improves on Elo in two ways. It tracks how sure it is about you (RD): win or lose, playing shrinks it, so your rating settles. And it updates the whole period at once, weighting games against uncertain opponents less. The 95% range is the honest read of your true strength — it's wide when you're new and tightens as you play.
Straight answers
What's the rating deviation (RD)?
It's the system's uncertainty about your rating — an error bar. A brand-new player starts around 350; as you play, win or lose, the RD shrinks and your rating becomes more trusted. Sit idle and it slowly grows again.
How is this different from Elo?
Two ways. Glicko-2 updates a whole rating period at once, weighting games against uncertain opponents less; and it carries RD and volatility, so a result against a well-established opponent moves you more precisely than one against an unknown.
What's volatility for?
It captures how erratic your recent results have been. A sudden run of surprises raises it, which lets your rating move faster until things settle — then it drops back down.
Educational chess content. Rating math uses the standard Elo model; results are estimates and vary by federation, pool and time control.