Model Comparison

Claude Mythos Preview vs Claude Opus 5Which is better in 2026?

Claude Opus 5 has a slight edge in benchmark performance. Claude Opus 5 is 5.0x cheaper per token.

Verdict: Claude Mythos Preview vs Claude Opus 5 — which is better?

Claude Mythos Preview (by Anthropic) and Claude Opus 5 (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.

Claude Mythos Preview outperforms in 0 benchmarks, while Claude Opus 5 is better at 1 benchmark (BrowseComp). Claude Opus 5 has a slight edge in benchmark performance.

On price, Claude Opus 5 is roughly 5.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Choose Claude Mythos Preview if…

  • you want predictable pricing at $25.00/M input and $125.00/M output

Choose Claude Opus 5 if…

  • you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
  • cost matters — it's about 5.0x cheaper per token

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Mythos Preview outperforms in 0 benchmarks, while Claude Opus 5 is better at 1 benchmark (BrowseComp).

Claude Opus 5 has a slight edge in benchmark performance.

Sat Jul 25 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Claude Opus 5 costs less

For input processing, Claude Mythos Preview ($25.00/1M tokens) is 5.0x more expensive than Claude Opus 5 ($5.00/1M tokens).

For output processing, Claude Mythos Preview ($125.00/1M tokens) is 5.0x more expensive than Claude Opus 5 ($25.00/1M tokens).

In conclusion, Claude Mythos Preview is more expensive than Claude Opus 5.*

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

Lowest available price from all providers
Sat Jul 25 2026 • llm-stats.com
Anthropic
Claude Mythos Preview
Input tokens$25.00
Output tokens$125.00
Best providerAnthropic
Anthropic
Claude Opus 5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Only Claude Opus 5 specifies input context (1,000,000 tokens). Only Claude Opus 5 specifies output context (128,000 tokens).

Anthropic
Claude Mythos Preview
Input- tokens
Output- tokens
Anthropic
Claude Opus 5
Input1,000,000 tokens
Output128,000 tokens
Sat Jul 25 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Mythos Preview and Claude Opus 5 support multimodal inputs.

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

Claude Mythos Preview

Text
Images
Audio
Video

Claude Opus 5

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 Mythos Preview

Proprietary

Closed source

Claude Opus 5

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 5 was released on 2026-07-24, while Claude Mythos Preview's release date is not specified.

We can confirm Claude Opus 5's release timeline, but cannot make a direct age comparison without Claude Mythos Preview's release date.

Claude Mythos Preview

—

Claude Opus 5

Jul 24, 2026

0 days ago

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

Claude Mythos Preview is available from Anthropic. Claude Opus 5 is available from Anthropic.

Claude Mythos Preview

anthropic logo
Anthropic
Input Price:Input: $25.00/1MOutput Price:Output: $125.00/1M

Claude Opus 5

anthropic logo
Anthropic
Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic

No standout differentiators in the data we have for this pair.

Anthropic
Larger context window (1,000,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher BrowseComp score (90.8% vs 86.9%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Mythos Preview and Claude Opus 5 side-by-side, then vote on the output you prefer.

Claude Mythos Preview
✓ Preferred
Claude Opus 5
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Mythos Preview
Anthropic
Claude Opus 5

FAQ

Common questions about Claude Mythos Preview vs Claude Opus 5.

Which is better, Claude Mythos Preview or Claude Opus 5?

Claude Opus 5 has a slight edge in benchmark performance. Claude Mythos Preview is made by Anthropic and Claude Opus 5 is made by Anthropic. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Mythos Preview compare to Claude Opus 5 in benchmarks?

Claude Mythos Preview scores CyBench: 100.0%, USAMO25: 97.6%, GPQA: 94.6%, SWE-Bench Verified: 93.9%, CharXiv-R: 93.2%. Claude Opus 5 scores BrowseComp: 90.8%, BioMysteryBench: 90.1%, OSWorld 2.0: 70.6%, DeepSWE 1.1: 68.8%, Humanity's Last Exam: 64.7%.

Is Claude Mythos Preview cheaper than Claude Opus 5?

Claude Opus 5 is 5.0x cheaper for input tokens. Claude Mythos Preview costs $25.00/M input and $125.00/M output via anthropic. Claude Opus 5 costs $5.00/M input and $25.00/M output via anthropic.

What are the context window sizes for Claude Mythos Preview and Claude Opus 5?

Claude Mythos Preview supports an unknown number of tokens and Claude Opus 5 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Mythos Preview and Claude Opus 5?

Key differences include input pricing ($25.00 vs $5.00/M). See the full comparison above for benchmark-by-benchmark results.

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