Gemini 2.5 Flash Preview 05-20 (thinking) vs Gemini 3.1 Pro Preview
Compare Gemini 2.5 Flash Preview 05-20 (thinking) and Gemini 3.1 Pro Preview, both from Google AI, context windows of 1.0M vs 1.0M, tested across 11 shared challenges. Updated May 2026.
Which is better, Gemini 2.5 Flash Preview 05-20 (thinking) or Gemini 3.1 Pro Preview?
Gemini 2.5 Flash Preview 05-20 (thinking) and Gemini 3.1 Pro Preview are both competitive models. Gemini 2.5 Flash Preview 05-20 (thinking) costs $0.15/M input tokens vs $2/M for Gemini 3.1 Pro Preview. Context windows: 1049K vs 1049K tokens. Compare their real outputs side by side below.
Key Differences Between Gemini 2.5 Flash Preview 05-20 (thinking) and Gemini 3.1 Pro Preview
Gemini 2.5 Flash Preview 05-20 (thinking) is made by google while Gemini 3.1 Pro Preview is from google. Gemini 2.5 Flash Preview 05-20 (thinking) has a 1049K token context window compared to Gemini 3.1 Pro Preview's 1049K. On pricing, Gemini 2.5 Flash Preview 05-20 (thinking) costs $0.15/M input tokens vs $2/M for Gemini 3.1 Pro Preview.
Per 1M tokens
Gemini 2.5 Flash Preview 05-20 (thinking) is cheaper on both — 13× input, 3.4× output
No community votes yet. On paper, Gemini 3.1 Pro Preview has the edge — bigger model tier, newer.
Gemini 2.5 Flash Preview 05-20 (thinking) is 3.4x cheaper per token — worth considering if cost matters.
Style Comparison
Gemini 3.1 Pro Preview uses 28.9x more hedging
