FIDE OFFICIAL RULES & RATING STANDARDS
FIDE Rating Calculator
Enter both ratings, pick the result, and see what the game is worth — using FIDE's own Elo formula, K-factors, and the 400-point rule.
Don't have a FIDE rating yet?
The calculator above works out a change to a rating you already hold — it doesn't tell you whether you're due one. Here's what actually earns a player their first FIDE rating:
- Play in a genuinely FIDE-rated event — registered with a national federation, run by a licensed arbiter, at a qualifying time control. A tournament isn't FIDE-rated just because it looks serious; ask the organizer if you're unsure.
- Score results in at least 5 games against opponents who already hold a FIDE rating — these don't have to come from a single tournament.
- Those games can be pooled from events played within roughly 26 months, so it's rarely a one-weekend achievement.
- The first published rating is calculated from those results and typically lands between 1400 and 2200.
Until all that happens, a player is simply “unrated” — completely normal, even after months of serious training. More detail in the FAQ below.
How It Works
The formula behind the number
Expected score
Based purely on the rating gap between both players, using FIDE's Elo curve.
K-factor
Controls how much a single game can move your rating — higher for newer players, lower once you're established.
400-point rule
A rating gap wider than 400 is capped at 400 before the expected score is worked out — straight from the FIDE handbook.
Questions, Answered
About ratings, briefly
Which K-factor should I pick?
Use 40 if you've played fewer than 30 rated games, or if you're under 18 and rated below 2300. Use 20 for most established players under 2400, and 10 once a player has reached 2400 at any point.
Why doesn't this match my official rating change exactly?
FIDE adds up every game in a tournament first and rounds the total once, so game-by-game figures can differ by a point from the published change. This tool shows one game at a time, with the unrounded number underneath so you can add them up yourself.
What is the 400-point rule?
If the gap between two players is wider than 400 points, FIDE treats it as exactly 400 when working out the expected score. It stops a single game against a far weaker or far stronger opponent from being worth almost nothing — or almost everything.
Does my opponent lose exactly what I gain?
In this tool, yes — we mirror it to show the exchange. In a real event it depends on their K-factor, so if you're on K=40 and they're on K=10, you'll gain considerably more than they lose.
How does a player get a FIDE rating in the first place?
By scoring results in at least 5 games against opponents who already hold a FIDE rating, played in FIDE-rated events. Those games don't need to come from one tournament — FIDE pools results from events played within roughly 26 months. The first published rating is worked out from those results and typically lands between 1400 and 2200. Until then, a player is unrated — which is completely normal, including for students who've trained for months.
How do I know if a tournament will actually count toward a FIDE rating?
Check for four things before you assume it counts: the organizer has registered the event with a national federation, a licensed arbiter is running it, the time control is long enough to qualify (classical/standard events are usually at least 60–90 minutes per player; rapid and blitz have their own shorter minimums), and it appears on the official FIDE calendar. If an organizer can't confirm these, ask directly whether the event is FIDE-rated before you play — a strong result in an unrated tournament won't move any FIDE number.
Is a rating the same as ability?
Not quite. A rating reflects results against rated opposition, so it lags real improvement — a student often plays noticeably better before the number catches up.