Claude Mythos Preview vs Claude Opus 4.8
Claude Mythos Preview significantly outperforms across most benchmarks. Claude Opus 4.8 is 5.0x cheaper per token.
Anthropic · Anthropic · Updated for 2026
Which is better?
Claude Mythos Preview outperforms in 11 benchmarks (BrowseComp, CharXiv-R, CyberGym, GPQA, Graphwalks BFS >128k, Humanity's Last Exam, SWE-bench Multilingual, SWE-Bench Multimodal, SWE-Bench Pro, SWE-Bench Verified, Terminal-Bench 2.0), while Claude Opus 4.8 is better at 1 benchmark (OSWorld-Verified). Claude Mythos Preview significantly outperforms across most benchmarks.
On price, Claude Opus 4.8 is roughly 5.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Based on current benchmark, pricing, and model metadata for 2026.
Choose Claude Mythos Preview
- you want the strongest raw capability — it leads on 11 of 12 shared benchmarks
Choose Claude Opus 4.8
- cost matters — it's about 5.0x cheaper per token
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
Claude Mythos Preview outperforms in 11 benchmarks (BrowseComp, CharXiv-R, CyberGym, GPQA, Graphwalks BFS >128k, Humanity's Last Exam, SWE-bench Multilingual, SWE-Bench Multimodal, SWE-Bench Pro, SWE-Bench Verified, Terminal-Bench 2.0), while Claude Opus 4.8 is better at 1 benchmark (OSWorld-Verified).
Claude Mythos Preview significantly outperforms across most benchmarks.
Arena Performance
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Mythos Preview ($25.00/1M tokens) is 5.0x more expensive than Claude Opus 4.8 ($5.00/1M tokens).
For output processing, Claude Mythos Preview ($125.00/1M tokens) is 5.0x more expensive than Claude Opus 4.8 ($25.00/1M tokens).
In conclusion, Claude Mythos Preview is more expensive than Claude Opus 4.8.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Only Claude Opus 4.8 specifies input context (1,000,000 tokens). Only Claude Opus 4.8 specifies output context (128,000 tokens).
Input Capabilities
Supported data types and modalities
Both Claude Mythos Preview and Claude Opus 4.8 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Mythos Preview
Claude Opus 4.8
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Opus 4.8 was released on 2026-05-28, while Claude Mythos Preview's release date is not specified.
We can confirm Claude Opus 4.8's release timeline, but cannot make a direct age comparison without Claude Mythos Preview's release date.
—
May 28, 2026
2 months ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Claude Mythos Preview is available from Anthropic. Claude Opus 4.8 is available from Anthropic, Vertex AI.
Claude Mythos Preview
Claude Opus 4.8
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Mythos Preview and Claude Opus 4.8 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Mythos Preview vs Claude Opus 4.8.