ELO, K-Factor & Other Terms Explained

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5 min read

New to rating systems? This guide explains every term you’ll run into while using TrackMyElo, in plain English. You don’t need a math background — just a few minutes.

ELO rating

An ELO rating is a single number that represents a player’s skill. It started in chess and is now used everywhere from tennis ladders to video games. After every match, points move from the loser to the winner. The key idea: how many points move depends on who was expected to win. Beat a much stronger player and you gain a lot; beat someone you were expected to beat and you gain only a little. Over time, everyone’s rating settles around their true skill level.

Starting ELO

The rating every new player begins with — 1000 by default in TrackMyElo, though you can set any value when you create a league. The exact number doesn’t matter on its own; what matters is the difference between players’ ratings. A common alternative is 1500 (the classic chess default).

K-factor

The K-factor controls how much a single match can change a rating — think of it as the “sensitivity” dial.

  • High K-factor (e.g. 40+): ratings swing quickly. Good for short seasons or casual groups where you want standings to react fast.
  • Low K-factor (e.g. 16–24): ratings move slowly and are more stable. Good for long-running leagues where you want ratings to reflect a large body of results.
  • 32 is a balanced default that works well for most groups.

If your standings feel too jumpy, lower the K-factor; if they take forever to reflect real skill, raise it.

Expected score

Behind the scenes, ELO converts the rating gap between two players into an expected score — essentially each player’s win probability. The bigger the favorite, the smaller their reward for winning and the bigger their penalty for losing. You never have to calculate this yourself; TrackMyElo does it automatically every time you record a match.

Score margin

By default, only the win or loss affects ratings — an 11–9 win counts the same as an 11–0 win. If you turn on “Score margin affects ELO,” the size of the victory matters too: blowouts move more points than nail-biters. You’ll also set a target score (e.g. 11 for ping pong) so margins are measured consistently.

Seeding

In a tournament, seeding is the order players are placed into the bracket. Seeding by ELO puts the highest-rated players in positions that keep them apart until later rounds, so the best matchups happen at the end. Turn seeding off for a random draw.

Single vs double elimination

  • Single elimination: one loss and you’re out. Fast and simple — best for larger fields or limited time.
  • Double elimination: you’re only out after two losses. Players who lose drop to a “losers’ bracket” and can fight back. Fairer, but takes about twice as many matches.

Bye

When the number of players isn’t a power of two (8, 16…), some players get a bye — a free pass through the first round. TrackMyElo assigns byes automatically, giving them to the top seeds.

“Affects ratings” toggle

Tournaments can either count toward your league’s ELO or be played just for fun. The “Affects ratings” toggle decides which. Turn it off for an exhibition bracket that won’t touch anyone’s rating. (Standalone “for fun” tournaments never affect ratings at all.)

Volume mode

Not every competition is head-to-head. Volume mode tracks a cumulative number instead — push-ups, miles run, hot dogs eaten — and awards ELO based on how you compare to a benchmark or the group’s session average. Great for challenges where there’s no single opponent.

Champion

The player who wins the final match of a tournament. Once a champion is decided, the bracket is marked complete and the winner is shown on the tournament card.