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Claude Mythos Preview vs GPT-6.1 Terra

Claude Mythos Preview and GPT-6.1 Terra are closely matched at 54.2 and 47.5 on the LLM Stats Score. GPT-6.1 Terra is 25.0x cheaper per token.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Mythos Preview and GPT-6.1 Terra are closely matched on the overall LLM Stats Score at 54.2 and 47.5.

On price, GPT-6.1 Terra is roughly 25.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Mythos Preview

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

Choose GPT-6.1 Terra

  • cost matters — it's about 25.0x cheaper per token

At a glance

The differences that matter most.

Claude Mythos Preview
Anthropic
GPT-6.1 Terra
OpenAI
Core performance indexes
LLM Stats Score
54.2
#7
47.5
#36
Reasoning
55.1
#4
49.0
#19
Coding
44.1
#5
37.1
#30
Agents
36.8
#22
38.8
#12
Cost, coverage & limits
Benchmark wins
—
—
Input price
$25.00 / M
$1.00 / M
Output price
$125.00 / M
$5.00 / M
Context window
—
1,050,000

Individual benchmarks

16 reported for Claude Mythos Preview · 8 for GPT-6.1 Terra

No common benchmarks found

Claude Mythos Preview and GPT-6.1 Terradon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

GPT-6.1 Terra costs less

For input processing, Claude Mythos Preview ($25.00/1M tokens) is 25.0x more expensive than GPT-6.1 Terra ($1.00/1M tokens).

For output processing, Claude Mythos Preview ($125.00/1M tokens) is 25.0x more expensive than GPT-6.1 Terra ($5.00/1M tokens).

In conclusion, Claude Mythos Preview is more expensive than GPT-6.1 Terra.*

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

Lowest available price from all providers
Thu Oct 29 2026 • llm-stats.com
Anthropic
Claude Mythos Preview
Input tokens$25.00
Output tokens$125.00
Best providerAnthropic
OpenAI
GPT-6.1 Terra
Input tokens$1.00
Output tokens$5.00
Best providerOpenAI
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Only GPT-6.1 Terra specifies input context (1,050,000 tokens). Only GPT-6.1 Terra specifies output context (128,000 tokens).

Anthropic
Claude Mythos Preview
Input- tokens
Output- tokens
OpenAI
GPT-6.1 Terra
Input1,050,000 tokens
Output128,000 tokens
Thu Oct 29 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Mythos Preview and GPT-6.1 Terra support multimodal inputs.

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

Claude Mythos Preview

Text
Images
Audio
Video

GPT-6.1 Terra

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

GPT-6.1 Terra

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-6.1 Terra was released on 2026-10-26, while Claude Mythos Preview's release date is not specified.

We can confirm GPT-6.1 Terra's release timeline, but cannot make a direct age comparison without Claude Mythos Preview's release date.

Claude Mythos Preview

—

GPT-6.1 Terra

Oct 26, 2026

3 days ago

Knowledge Cutoff

When training data ends

GPT-6.1 Terra has a documented knowledge cutoff of 2026-06-01, while Claude Mythos Preview's cutoff date is not specified.

We can confirm GPT-6.1 Terra's training data extends to 2026-06-01, but cannot make a direct comparison without Claude Mythos Preview's cutoff date.

Claude Mythos Preview

—

GPT-6.1 Terra

Jun 2026

Provider Availability

Claude Mythos Preview is available from Anthropic. GPT-6.1 Terra is available from OpenAI.

Claude Mythos Preview

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

GPT-6.1 Terra

openai logo
OpenAI
Input Price:Input: $1.00/1MOutput Price:Output: $5.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Mythos Preview and GPT-6.1 Terra side-by-side, then vote on the output you prefer.

Claude Mythos Preview
✓ Preferred
GPT-6.1 Terra
Open in Playground

FAQ

Common questions about Claude Mythos Preview vs GPT-6.1 Terra.

Which is better, Claude Mythos Preview or GPT-6.1 Terra?

Claude Mythos Preview and GPT-6.1 Terra are closely matched on the LLM Stats Score at 54.2 and 47.5. Claude Mythos Preview is made by Anthropic and GPT-6.1 Terra is made by OpenAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Mythos Preview compare to GPT-6.1 Terra in benchmarks?

Claude Mythos Preview scores CyBench: 100.0%, USAMO25: 97.6%, GPQA: 94.6%, SWE-Bench Verified: 93.9%, CharXiv-R: 93.2%. GPT-6.1 Terra scores HealthBench Consensus: 95.1%, HealthBench Professional: 62.7%, Agents' Last Exam: 60.0%, Terminal-Bench-Science 0.1: 58.3%, MentalHealthBench: 55.5%.

Is Claude Mythos Preview cheaper than GPT-6.1 Terra?

GPT-6.1 Terra is 25.0x cheaper for input tokens. Claude Mythos Preview costs $25.00/M input and $125.00/M output via anthropic. GPT-6.1 Terra costs $1.00/M input and $5.00/M output via openai.

What are the context window sizes for Claude Mythos Preview and GPT-6.1 Terra?

Claude Mythos Preview supports an unknown number of tokens and GPT-6.1 Terra supports 1.1M 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 GPT-6.1 Terra?

Key differences include LLM Stats Score (54.2 vs 47.5), input pricing ($25.00 vs $1.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Mythos Preview and GPT-6.1 Terra?

Claude Mythos Preview is developed by Anthropic and GPT-6.1 Terra is developed by OpenAI.

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