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, in 1 community votes, gemini 3.1 pro preview wins 100% of head-to-head duels, context windows of 1.0M vs 1.0M, tested across 11 shared challenges. Updated April 2026.

Which is better, Gemini 2.5 Flash Preview 05-20 (thinking) or Gemini 3.1 Pro Preview?

Gemini 3.1 Pro Preview is the better choice overall, winning 100% of 1 blind community votes on Rival. 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. In community voting, In 1 community votes, Gemini 3.1 Pro Preview wins 100% of head-to-head duels.

In 1 community votes, Gemini 3.1 Pro Preview wins 100% of head-to-head duels. Based on blind community voting from the Rival open dataset of 1+ human preference judgments for this pair.

Our Verdict
Gemini 3.1 Pro Preview
Gemini 3.1 Pro PreviewWinner
Gemini 2.5 Flash Preview 05-20 (thinking)
Gemini 2.5 Flash Preview 05-20 (thinking)Runner-up

Pick Gemini 3.1 Pro Preview. In 1 blind votes, Gemini 3.1 Pro Preview wins 100% of the time. That's not luck.

Gemini 2.5 Flash Preview 05-20 (thinking) is 3.4x cheaper per token — worth considering if cost matters.

Clear winner
Writing DNA

Style Comparison

Similarity
93%

Gemini 3.1 Pro Preview uses 28.9x more hedging

Gemini 2.5 Flash Preview 05-20 (thinking)
Gemini 3.1 Pro Preview
70%Vocabulary54%
11wSentence Length18w
0.00Hedging0.29
4.2Bold4.9
7.3Lists3.3
0.00Emoji0.00
0.00Headings0.72
0.00Transitions0.14
Based on 3 + 23 text responses
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