GPT 5.3 Codex vs Claude Sonnet 5
OpenAI's most advanced agentic coding model with 400K context.
Anthropic's fifth-generation Sonnet — near-Opus intelligence at Sonnet speed and price.
No captured outputs for these models yet.
Frequently Asked Questions: GPT 5.3 Codex vs Claude Sonnet 5▼
Which is better, GPT 5.3 Codex or Claude Sonnet 5?
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Based on the Capability Index, GPT 5.3 Codex scores higher (87.0 vs 80.1). However, "better" depends on your use case — pricing, speed, context window, and specific capability needs all matter.
Which is cheaper, GPT 5.3 Codex or Claude Sonnet 5?
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GPT 5.3 Codex has a lower blended cost. GPT 5.3 Codex: $1.75 input / $14.00 output. Claude Sonnet 5: $3.00 input / $15.00 output.
Which has a larger context window, GPT 5.3 Codex or Claude Sonnet 5?
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Claude Sonnet 5 has a larger context window: GPT 5.3 Codex supports 400K tokens vs Claude Sonnet 5 at 1M tokens.
Do both GPT 5.3 Codex and Claude Sonnet 5 support vision?
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Yes, both GPT 5.3 Codex and Claude Sonnet 5 support vision/image input.
What are the key differences between GPT 5.3 Codex and Claude Sonnet 5?
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Key differences: GPT 5.3 Codex has a notably higher capability index (6.9 point gap). Compare full specs on this page.
Which model should I choose for my use case?
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If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both GPT 5.3 Codex and Claude Sonnet 5 for free on idapt.app to see which performs better for your specific needs.