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Claude 3.5 Sonnet vs GPT-5 Codex

Comparing Claude 3.5 Sonnet and GPT-5 Codex across benchmarks, pricing, and capabilities.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude 3.5 Sonnet and GPT-5 Codex trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.

Based on current benchmark, pricing, and model metadata for 2026.

Choose Claude 3.5 Sonnet

  • you want predictable pricing at $3.00/M input and $15.00/M output

Choose GPT-5 Codex

  • you want the most recent training data — it shipped Sep 2025

At a glance

The differences that matter most.

Claude 3.5 Sonnet
Anthropic
GPT-5 Codex
OpenAI
Benchmark wins
—
—
Input price
$3.00 / M
— / M
Output price
$15.00 / M
— / M
Context window
200,000
—
Released
Jun 2024
Sep 2025
License
Proprietary
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Claude 3.5 Sonnet and GPT-5 Codexdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only Claude 3.5 Sonnet specifies input context (200,000 tokens). Only Claude 3.5 Sonnet specifies output context (200,000 tokens).

Anthropic
Claude 3.5 Sonnet
Input200,000 tokens
Output200,000 tokens
OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
Wed Aug 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude 3.5 Sonnet supports multimodal inputs, whereas GPT-5 Codex does not.

Claude 3.5 Sonnet can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude 3.5 Sonnet

Text
Images
Audio
Video

GPT-5 Codex

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude 3.5 Sonnet

Proprietary

Closed source

GPT-5 Codex

Proprietary

Closed source

Release Timeline

When each model was launched

Claude 3.5 Sonnet was released on 2024-06-21, while GPT-5 Codex was released on 2025-09-15.

GPT-5 Codex is 15 months newer than Claude 3.5 Sonnet.

Claude 3.5 Sonnet

Jun 21, 2024

2.2 years ago

GPT-5 Codex

Sep 15, 2025

11 months ago

1.2yr newer

Knowledge Cutoff

When training data ends

GPT-5 Codex has a documented knowledge cutoff of 2024-09-30, while Claude 3.5 Sonnet's cutoff date is not specified.

We can confirm GPT-5 Codex's training data extends to 2024-09-30, but cannot make a direct comparison without Claude 3.5 Sonnet's cutoff date.

Claude 3.5 Sonnet

—

GPT-5 Codex

Sep 2024

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude 3.5 Sonnet and GPT-5 Codex side-by-side, then vote on the output you prefer.

Claude 3.5 Sonnet
✓ Preferred
GPT-5 Codex
Open in Playground

FAQ

Common questions about Claude 3.5 Sonnet vs GPT-5 Codex.

Which is better, Claude 3.5 Sonnet or GPT-5 Codex?

Claude 3.5 Sonnet (Anthropic) and GPT-5 Codex (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Claude 3.5 Sonnet compare to GPT-5 Codex in benchmarks?

Claude 3.5 Sonnet scores GSM8k: 96.4%, BIG-Bench Hard: 93.1%, HumanEval: 92.0%, MGSM: 91.6%, MMLU: 90.4%. GPT-5 Codex scores SWE-Bench Verified: 74.5%.

What are the context window sizes for Claude 3.5 Sonnet and GPT-5 Codex?

Claude 3.5 Sonnet supports 200K tokens and GPT-5 Codex supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude 3.5 Sonnet and GPT-5 Codex?

Key differences include multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude 3.5 Sonnet and GPT-5 Codex?

Claude 3.5 Sonnet is developed by Anthropic and GPT-5 Codex is developed by OpenAI.

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