Gemini 2.5 Flash Preview 05-20 (thinking) vs Claude Sonnet 4

Compare Gemini 2.5 Flash Preview 05-20 (thinking) by Google AI against Claude Sonnet 4 by Anthropic, context windows of 1.0M vs 200K, tested across 12 shared challenges. Updated April 2026.

Which is better, Gemini 2.5 Flash Preview 05-20 (thinking) or Claude Sonnet 4?

Gemini 2.5 Flash Preview 05-20 (thinking) and Claude Sonnet 4 are both competitive models. Gemini 2.5 Flash Preview 05-20 (thinking) costs $0.15/M input tokens vs $3/M for Claude Sonnet 4. Context windows: 1049K vs 200K tokens. Compare their real outputs side by side below.

Key Differences Between Gemini 2.5 Flash Preview 05-20 (thinking) and Claude Sonnet 4

Gemini 2.5 Flash Preview 05-20 (thinking) is made by google while Claude Sonnet 4 is from anthropic. Gemini 2.5 Flash Preview 05-20 (thinking) has a 1049K token context window compared to Claude Sonnet 4's 200K. On pricing, Gemini 2.5 Flash Preview 05-20 (thinking) costs $0.15/M input tokens vs $3/M for Claude Sonnet 4.

Our Verdict
Gemini 2.5 Flash Preview 05-20 (thinking)
Gemini 2.5 Flash Preview 05-20 (thinking)
Claude Sonnet 4
Claude Sonnet 4

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Gemini 2.5 Flash Preview 05-20 (thinking) is 4.3x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
80%

Claude Sonnet 4 uses 40.1x more hedging

Gemini 2.5 Flash Preview 05-20 (thinking)
Claude Sonnet 4
70%Vocabulary62%
11wSentence Length111w
0.00Hedging0.40
4.2Bold5.0
7.3Lists9.3
0.00Emoji0.88
0.00Headings2.16
0.00Transitions0.33
Based on 3 + 17 text responses
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Gemini 2.5 Flash Preview 05-20 (thinking)Claude Sonnet 4

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
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