Model Comparison

GPT-5.4 vs Claude Mythos PreviewWhich is better in 2026?

Claude Mythos Preview significantly outperforms across most benchmarks. GPT-5.4 is 8.9x cheaper per token.

Verdict: GPT-5.4 vs Claude Mythos Preview — which is better?

GPT-5.4 (by OpenAI) and Claude Mythos Preview (by Anthropic) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

GPT-5.4 outperforms in 0 benchmarks, while Claude Mythos Preview is better at 7 benchmarks (BrowseComp, GPQA, Graphwalks BFS >128k, Humanity's Last Exam, OSWorld-Verified, SWE-Bench Pro, Terminal-Bench 2.0). Claude Mythos Preview significantly outperforms across most benchmarks.

On price, GPT-5.4 is roughly 8.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Choose GPT-5.4 if…

  • cost matters — it's about 8.9x cheaper per token

Choose Claude Mythos Preview if…

  • you want the strongest raw capability — it leads on 7 of 7 shared benchmarks
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Performance Benchmarks

Comparative analysis across standard metrics

7 benchmarks

GPT-5.4 outperforms in 0 benchmarks, while Claude Mythos Preview is better at 7 benchmarks (BrowseComp, GPQA, Graphwalks BFS >128k, Humanity's Last Exam, OSWorld-Verified, SWE-Bench Pro, Terminal-Bench 2.0).

Claude Mythos Preview significantly outperforms across most benchmarks.

Sun Jun 07 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.4 costs less

For input processing, GPT-5.4 ($2.50/1M tokens) is 10.0x cheaper than Claude Mythos Preview ($25.00/1M tokens).

For output processing, GPT-5.4 ($15.00/1M tokens) is 8.3x cheaper than Claude Mythos Preview ($125.00/1M tokens).

In conclusion, Claude Mythos Preview is more expensive than GPT-5.4.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Sun Jun 07 2026 • llm-stats.com
OpenAI
GPT-5.4
Input tokens$2.50
Output tokens$15.00
Best providerOpenAI
Anthropic
Claude Mythos Preview
Input tokens$25.00
Output tokens$125.00
Best providerAnthropic
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Only GPT-5.4 specifies input context (1,000,000 tokens). Only GPT-5.4 specifies output context (128,000 tokens).

OpenAI
GPT-5.4
Input1,000,000 tokens
Output128,000 tokens
Anthropic
Claude Mythos Preview
Input- tokens
Output- tokens
Sun Jun 07 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.4 and Claude Mythos Preview support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

GPT-5.4

Text
Images
Audio
Video

Claude Mythos Preview

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.

GPT-5.4

Proprietary

Closed source

Claude Mythos Preview

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.4 was released on 2026-03-05, while Claude Mythos Preview's release date is not specified.

We can confirm GPT-5.4's release timeline, but cannot make a direct age comparison without Claude Mythos Preview's release date.

GPT-5.4

Mar 5, 2026

3 months ago

Claude Mythos Preview

—

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

GPT-5.4 is available from OpenAI. Claude Mythos Preview is available from Anthropic.

GPT-5.4

openai logo
OpenAI
Input Price:Input: $2.50/1MOutput Price:Output: $15.00/1M

Claude Mythos Preview

anthropic logo
Anthropic
Input Price:Input: $25.00/1MOutput Price:Output: $125.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (1,000,000 tokens)
Less expensive input tokens
Less expensive output tokens
Anthropic
Higher BrowseComp score (86.9% vs 82.7%)
Higher GPQA score (94.6% vs 92.8%)
Higher Graphwalks BFS >128k score (80.0% vs 21.4%)
Higher Humanity's Last Exam score (64.7% vs 39.8%)
Higher OSWorld-Verified score (79.6% vs 75.0%)
Higher SWE-Bench Pro score (77.8% vs 57.7%)
Higher Terminal-Bench 2.0 score (82.0% vs 75.1%)

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT-5.4
Anthropic
Claude Mythos Preview

FAQ

Common questions about GPT-5.4 vs Claude Mythos Preview.

Which is better, GPT-5.4 or Claude Mythos Preview?

Claude Mythos Preview significantly outperforms across most benchmarks. GPT-5.4 is made by OpenAI and Claude Mythos Preview is made by Anthropic. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT-5.4 compare to Claude Mythos Preview in benchmarks?

GPT-5.4 scores Tau2 Telecom: 98.9%, ARC-AGI: 93.7%, Graphwalks BFS <128k: 93.0%, GPQA: 92.8%, Graphwalks parents <128k: 89.8%. Claude Mythos Preview scores CyBench: 100.0%, USAMO25: 97.6%, GPQA: 94.6%, SWE-Bench Verified: 93.9%, CharXiv-R: 93.2%.

Is GPT-5.4 cheaper than Claude Mythos Preview?

GPT-5.4 is 10.0x cheaper for input tokens. GPT-5.4 costs $2.50/M input and $15.00/M output via openai. Claude Mythos Preview costs $25.00/M input and $125.00/M output via anthropic.

What are the context window sizes for GPT-5.4 and Claude Mythos Preview?

GPT-5.4 supports 1.0M tokens and Claude Mythos Preview 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 GPT-5.4 and Claude Mythos Preview?

Key differences include input pricing ($2.50 vs $25.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.4 and Claude Mythos Preview?

GPT-5.4 is developed by OpenAI and Claude Mythos Preview is developed by Anthropic.

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