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Claude Opus 4 vs GPT-5-Codex

2 vs 0 benchmarks won

Anthropic
Claude Opus 4
OpenAI
GPT-5-Codex
Overview
CompanyAnthropicOpenAI
Release dateMay 22 2025Sep 15 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
79.6%
Software engineering
SWE-Bench Verified
72.5%
Multimodal understanding
MMMU
Timeline
Release gapClaude Opus 4 shipped 116 days before GPT-5-Codex

Which is better: Claude Opus 4 or GPT-5-Codex?

Claude Opus 4 leads GPT-5-Codex on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude Opus 4 shipped 116 days before GPT-5-Codex, 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 — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude Opus 4 released?
Claude Opus 4 was released by Anthropic on May 22 2025.
When was GPT-5-Codex released?
GPT-5-Codex was released by OpenAI on Sep 15 2025.

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