Model Comparison

Claude Opus 5 vs Kimi K2 BaseWhich is better in 2026?

Comparing Claude Opus 5 and Kimi K2 Base across benchmarks, pricing, and capabilities.

Verdict: Claude Opus 5 vs Kimi K2 Base — which is better?

Claude Opus 5 (by Anthropic) and Kimi K2 Base (by Moonshot AI) 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.

Choose Claude Opus 5 if…

  • you want the most recent training data — it shipped Jul 2026

Choose Kimi K2 Base if…

  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Claude Opus 5 and Kimi K2 Basedon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

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 Opus 5
Input1,000,000 tokens
Output128,000 tokens
Moonshot AI
Kimi K2 Base
Input- tokens
Output- tokens
Sun Jul 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 5 supports multimodal inputs, whereas Kimi K2 Base does not.

Claude Opus 5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 5

Text
Images
Audio
Video

Kimi K2 Base

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 5 is licensed under a proprietary license, while Kimi K2 Base uses MIT.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Opus 5

Proprietary

Closed source

Kimi K2 Base

MIT

Open weights

Release Timeline

When each model was launched

Claude Opus 5 was released on 2026-07-24, while Kimi K2 Base was released on 2025-07-11.

Claude Opus 5 is 13 months newer than Kimi K2 Base.

Claude Opus 5

Jul 24, 2026

1 days ago

1.0yr newer
Kimi K2 Base

Jul 11, 2025

1.0 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→

Key Takeaways

Anthropic
Larger context window (1,000,000 tokens)
Supports multimodal inputs
Moonshot AI
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Opus 5 and Kimi K2 Base side-by-side, then vote on the output you prefer.

Claude Opus 5
✓ Preferred
Kimi K2 Base
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Opus 5
Moonshot AI
Kimi K2 Base

FAQ

Common questions about Claude Opus 5 vs Kimi K2 Base.

Which is better, Claude Opus 5 or Kimi K2 Base?

Claude Opus 5 (Anthropic) and Kimi K2 Base (Moonshot AI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Claude Opus 5 compare to Kimi K2 Base in benchmarks?

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%. Kimi K2 Base scores C-Eval: 92.5%, GSM8k: 92.1%, MMLU-redux-2.0: 90.2%, MMLU: 87.8%, TriviaQA: 85.1%.

What are the context window sizes for Claude Opus 5 and Kimi K2 Base?

Claude Opus 5 supports 1.0M tokens and Kimi K2 Base 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 Opus 5 and Kimi K2 Base?

Key differences include multimodal support (yes vs no), licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 5 and Kimi K2 Base?

Claude Opus 5 is developed by Anthropic and Kimi K2 Base is developed by Moonshot AI.

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