Gemini 2.5 Flash Preview vs Gemini 3.1 Pro Preview
Compare Gemini 2.5 Flash Preview and Gemini 3.1 Pro Preview, both from Google AI, context windows of 1.0M vs 1.0M, tested across 26 shared challenges. Updated May 2026.
Which is better, Gemini 2.5 Flash Preview or Gemini 3.1 Pro Preview?
Gemini 2.5 Flash Preview and Gemini 3.1 Pro Preview are both competitive models. Gemini 2.5 Flash Preview 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 and Gemini 3.1 Pro Preview
Gemini 2.5 Flash Preview is made by google while Gemini 3.1 Pro Preview is from google. Gemini 2.5 Flash Preview has a 1049K token context window compared to Gemini 3.1 Pro Preview's 1049K. On pricing, Gemini 2.5 Flash Preview costs $0.15/M input tokens vs $2/M for Gemini 3.1 Pro Preview.
Per 1M tokens
Gemini 2.5 Flash Preview is cheaper on both — 13× input, 20× output
No community votes yet. On paper, Gemini 3.1 Pro Preview has the edge — bigger model tier, newer.
Gemini 2.5 Flash Preview is 20x cheaper per token — worth considering if cost matters.
Style Comparison
Gemini 3.1 Pro Preview uses 8.1x more headings
