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Claude Mythos 5.1 vs Kimi-k1.5

Claude Mythos 5.1 leads the LLM Stats Score 45.1 to 17.3.

Anthropic · Moonshot AI · Updated for 2026

Which is better?

Claude Mythos 5.1 leads the overall LLM Stats Score 45.1 to 17.3, ranking #31 overall.

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

Choose Claude Mythos 5.1

  • overall performance matters — it scores 45.1 and ranks #31 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

Choose Kimi-k1.5

  • you are already invested in the Moonshot AI ecosystem

At a glance

The differences that matter most.

Claude Mythos 5.1
Anthropic
Kimi-k1.5
Moonshot AI
Core performance indexes
LLM Stats Score
45.1
#31
17.3
#216
Reasoning
44.4
#34
16.5
#213
Cost, coverage & limits
Benchmark wins
—
—
Input price
$10.00 / M
— / M
Output price
$50.00 / M
— / M
Context window
1,000,000
—

Individual benchmarks

1 reported for Claude Mythos 5.1 · 9 for Kimi-k1.5

No common benchmarks found

Claude Mythos 5.1 and Kimi-k1.5don'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

Context Window

Maximum input and output token capacity

Only Claude Mythos 5.1 specifies input context (1,000,000 tokens). Only Claude Mythos 5.1 specifies output context (128,000 tokens).

Anthropic
Claude Mythos 5.1
Input1,000,000 tokens
Output128,000 tokens
Moonshot AI
Kimi-k1.5
Input- tokens
Output- tokens
Wed Sep 09 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Mythos 5.1 and Kimi-k1.5 support multimodal inputs.

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

Claude Mythos 5.1

Text
Images
Audio
Video

Kimi-k1.5

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 5.1

Proprietary

Closed source

Kimi-k1.5

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Mythos 5.1 was released on 2026-09-01, while Kimi-k1.5 was released on 2025-01-20.

Claude Mythos 5.1 is 20 months newer than Kimi-k1.5.

Claude Mythos 5.1

Sep 1, 2026

1 weeks ago

1.6yr newer
Kimi-k1.5

Jan 20, 2025

1.6 years 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

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Mythos 5.1 and Kimi-k1.5 side-by-side, then vote on the output you prefer.

Claude Mythos 5.1
✓ Preferred
Kimi-k1.5
Open in Playground

FAQ

Common questions about Claude Mythos 5.1 vs Kimi-k1.5.

Which is better, Claude Mythos 5.1 or Kimi-k1.5?

Claude Mythos 5.1 leads the LLM Stats Score 45.1 to 17.3. Claude Mythos 5.1 is made by Anthropic and Kimi-k1.5 is made by Moonshot AI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Mythos 5.1 compare to Kimi-k1.5 in benchmarks?

Claude Mythos 5.1 scores Terminal-Bench 4.0: 60.9%. Kimi-k1.5 scores MATH-500: 96.2%, CLUEWSC: 91.4%, C-Eval: 88.3%, MMLU: 87.4%, IFEval: 87.2%.

What are the context window sizes for Claude Mythos 5.1 and Kimi-k1.5?

Claude Mythos 5.1 supports 1.0M tokens and Kimi-k1.5 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 Mythos 5.1 and Kimi-k1.5?

Key differences include LLM Stats Score (45.1 vs 17.3). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Mythos 5.1 and Kimi-k1.5?

Claude Mythos 5.1 is developed by Anthropic and Kimi-k1.5 is developed by Moonshot AI.

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