Chess Rating Calculator: Elo

Your rating is a number you only ever hear about second-hand — weeks after the tournament, when the list is finally published. This app gives it to you the moment the game ends, and it answers the question that actually matters: what will the next tournament do to it? You enter the opponent's rating and the result. That is the whole input. There is no board, no engine, no account and no server — just the published Elo mathematics, run on your own results, offline. HOW IT WORKS • Expected score E = 1 / (1 + 10^((Rb − Ra) / 400)), rating change ΔR = K × (S − E) — the two lines every federation formula starts from. • Choose your rule set: tiered K (40 / 20 / 10 by rating and games played), a simplified formula with a bonus threshold, or a fixed K of 10 to 40 for club ladders and online leagues. • The 400-point rule can be switched on or off. • Tournament mode is round by round: the total rating change, the performance rating and the TPR when you close it. • No rating yet? Five or more games produce your first one — average opponent plus the dp table. WHAT THE NEXT TOURNAMENT DOES TO IT This is the screen the app exists for, and it works in both directions. • Forward: set the rounds, the average opponent rating and a score. Nine rounds against an average of 1850, score 5½ — there is your new rating, before a single move. • Backwards: name a target rating and it solves the same equation for the smallest half-point score that gets you there. If a perfect score still falls short, it says so. • And the question nobody likes asking: exactly how many points one loss would cost you. THE CAREER LEDGER • Your rating curve across every saved tournament, with the 2000, 2200 and 2400 lines on it. • Peak rating, and the points left to the next threshold. • Games this month, average performance rating, and your best win. • A monthly calendar of the days you played. • Daily, weekly and monthly challenges, plus 95 badges for what actually moves a rating: playing often, beating players above you, finishing unbeaten, crossing a threshold. WHAT IT IS — AND IS NOT Every number here is an estimate for personal tracking, produced with the same published mathematics that federation systems use. It is not an official rating, this app is not affiliated with or endorsed by any chess federation, and nothing in it can be used to enter a tournament. It also will not reproduce the rating you see on online chess sites — those use Glicko-style systems with their own parameters. This is federation-style Elo. Your games stay on your device. No account, no analytics, no connection required. CHESS RATING PRO The app is premium: the calculator, tournament mode, the projection screen and the career ledger are part of Chess Rating Pro. • A recurring subscription, with the first period at a reduced price • Or a one-time purchase that never renews Subscriptions renew automatically unless cancelled at least 24 hours before the current period ends. Payment is charged to your Apple Account at confirmation of purchase, and renewal is charged within 24 hours before the period ends. Manage or cancel any time in your Apple Account settings. The one-time option is a single payment and is not a subscription. Terms of Use: https://doesonejob.com/eloledger/terms/ Privacy Policy: https://doesonejob.com/eloledger/privacy/ Questions or ideas: eloledger@doesonejob.com