Head-to-Head Model Showdown
Claude Opus 5.5 vs Gemini 3.1 Pro
Claude Opus 5.5 vs Gemini 3.1 Pro side by side: arena.ai text score, list price per 1M tokens, context window and licence, with sources. Data checked 2026-10-11.
Executive Verdict
On the arena.ai text leaderboard, Claude Opus 5.5 scores 1507 (±8, #2) and Gemini 3.1 Pro scores 1487 (±3, #17). Claude Opus 5.5 leads by 20 points, outside the margin of error. Claude Opus 5.5: $4.00 input / $20.00 output per 1M tokens. Gemini 3.1 Pro: $2.00 / $12.00. Blended at 3 input : 1 output, Gemini 3.1 Pro costs 44% less ($4.50 vs $8.00 per 1M tokens). Context windows are about the same: Claude Opus 5.5 1M tokens, Gemini 3.1 Pro 1M tokens. Both are proprietary and available only as hosted APIs.