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Claude Sonnet 4.5 vs Gemini 3.1 Flash

Anthropic Claude Sonnet 4.5 vs Google Gemini 3.1 Flash — side-by-side specs.

Anthropic
Claude Sonnet 4.5
Google
Gemini 3.1 Flash
Overview
CompanyAnthropicGoogle
Release dateSep 29 2025Feb 26 2026
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Coding
SWE-Bench Verified
77.2%
Science
GPQA Diamond
83.4%
Multimodal
MMMU
68%
Timeline
Release gapClaude Sonnet 4.5 shipped 150 days before Gemini 3.1 Flash

Which is better: Claude Sonnet 4.5 or Gemini 3.1 Flash?

Claude Sonnet 4.5 and Gemini 3.1 Flash don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude Sonnet 4.5 shipped 150 days before Gemini 3.1 Flash, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — Claude Sonnet 4.5 and Gemini 3.1 Flash don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Claude Sonnet 4.5 released?
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
When was Gemini 3.1 Flash released?
Gemini 3.1 Flash was released by Google on Feb 26 2026.

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