Elo Ranker

Rank any JSON list by repeatedly picking the better of two items. Elo math turns your picks into a ranking you can download.

1 · Your list

Paste JSON

An array of strings or objects:

You can also drop a .json file anywhere on this page. Lists of a few thousand items work fine.

2 · Which is better?

Tap a card, swipe left or right, or use the ← → keys. Press ↓/T for a tie, ↑/S to skip, and U or Ctrl+Z to undo. The top card is Left.

3 · Ranking & export

Wrap the JSON with metadata: {exportedAt, settings, ranking}

Live leaderboard

Settings

Starting rating K-factor Pair selection

Decay K as an item plays more games: K = max(10, 40 / (1 + games/10)) Tagging mode: show image URLs (.png, .jpg, .gif, .webp, .svg) as images

Elo: E = 1 / (1 + 10^((Rb − Ra)/400)), R′ = R + K·(S − E), where S is 1 for a win, 0.5 for a tie and 0 for a loss. Semi-random mode favors items with few games, then pairs each with an opponent of similar rating (weight e^(−|Δ|/200)). It avoids pairs you have already seen.

Use it for any data

This tool can rank fantasy players, product ideas, logos, photos, headlines, or any text snippets. You can also use it for data tagging. Put image URLs in the label field and turn on tagging mode in Settings to compare pictures. Long text wraps inside the cards. Every exported item keeps all its original fields and gains rank, elo, games, wins, losses and ties, so you can set thresholds or buckets on the score afterward.

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