Model Comparison

Kimi K2.5 vs GPT-5.5 Instant

Kimi K2.5 significantly outperforms across most benchmarks. Kimi K2.5 is 9.4x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

5 benchmarks

Kimi K2.5 outperforms in 4 benchmarks (AIME 2025, GPQA, MMMU-Pro, OmniDocBench 1.5), while GPT-5.5 Instant is better at 1 benchmark (CharXiv-R).

Kimi K2.5 significantly outperforms across most benchmarks.

Wed May 06 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Kimi K2.5 costs less

For input processing, Kimi K2.5 ($0.60/1M tokens) is 8.3x cheaper than GPT-5.5 Instant ($5.00/1M tokens).

For output processing, Kimi K2.5 ($3.00/1M tokens) is 10.0x cheaper than GPT-5.5 Instant ($30.00/1M tokens).

In conclusion, GPT-5.5 Instant is more expensive than Kimi K2.5.*

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

Lowest available price from all providers
Wed May 06 2026 • llm-stats.com
Moonshot AI
Kimi K2.5
Input tokens$0.60
Output tokens$3.00
Best providerFireworks
OpenAI
GPT-5.5 Instant
Input tokens$5.00
Output tokens$30.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.5 Instant accepts 400,000 input tokens compared to Kimi K2.5's 262,100 tokens. Kimi K2.5 can generate longer responses up to 262,100 tokens, while GPT-5.5 Instant is limited to 128,000 tokens.

Moonshot AI
Kimi K2.5
Input262,100 tokens
Output262,100 tokens
OpenAI
GPT-5.5 Instant
Input400,000 tokens
Output128,000 tokens
Wed May 06 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Kimi K2.5 and GPT-5.5 Instant support multimodal inputs.

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

Kimi K2.5

Text
Images
Audio
Video

GPT-5.5 Instant

Text
Images
Audio
Video

License

Usage and distribution terms

Kimi K2.5 is licensed under MIT, while GPT-5.5 Instant uses a proprietary license.

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

Kimi K2.5

MIT

Open weights

GPT-5.5 Instant

Proprietary

Closed source

Release Timeline

When each model was launched

Kimi K2.5 was released on 2026-01-27, while GPT-5.5 Instant was released on 2026-05-05.

GPT-5.5 Instant is 3 months newer than Kimi K2.5.

Kimi K2.5

Jan 27, 2026

3 months ago

GPT-5.5 Instant

May 5, 2026

1 days ago

3mo newer

Knowledge Cutoff

When training data ends

GPT-5.5 Instant has a documented knowledge cutoff of 2025-08-31, while Kimi K2.5's cutoff date is not specified.

We can confirm GPT-5.5 Instant's training data extends to 2025-08-31, but cannot make a direct comparison without Kimi K2.5's cutoff date.

Kimi K2.5

—

GPT-5.5 Instant

Aug 2025

Provider Availability

Kimi K2.5 is available from Fireworks, Moonshot AI. GPT-5.5 Instant is available from OpenAI.

Kimi K2.5

fireworks logo
Fireworks
Input Price:Input: $0.60/1MOutput Price:Output: $3.00/1M
moonshot logo
Unknown Organization
Input Price:Input: $0.60/1MOutput Price:Output: $3.00/1M

GPT-5.5 Instant

openai logo
OpenAI
Input Price:Input: $5.00/1MOutput Price:Output: $30.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Moonshot AI
Less expensive input tokens
Less expensive output tokens
Has open weights
Higher AIME 2025 score (96.1% vs 81.2%)
Higher GPQA score (87.6% vs 85.6%)
Higher MMMU-Pro score (78.5% vs 76.0%)
Higher OmniDocBench 1.5 score (88.8% vs 87.5%)
OpenAI
Larger context window (400,000 tokens)
Higher CharXiv-R score (81.6% vs 77.5%)

Detailed Comparison

AI Model Comparison Table
Feature
Moonshot AI
Kimi K2.5
OpenAI
GPT-5.5 Instant

FAQ

Common questions about Kimi K2.5 vs GPT-5.5 Instant.

Which is better, Kimi K2.5 or GPT-5.5 Instant?

Kimi K2.5 significantly outperforms across most benchmarks. Kimi K2.5 is made by Moonshot AI and GPT-5.5 Instant is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Kimi K2.5 compare to GPT-5.5 Instant in benchmarks?

Kimi K2.5 scores AIME 2025: 96.1%, HMMT 2025: 95.4%, InfoVQAtest: 92.6%, OCRBench: 92.3%, MathVista-Mini: 90.1%. GPT-5.5 Instant scores HealthBench Consensus: 94.7%, OmniDocBench 1.5: 87.5%, GPQA: 85.6%, CharXiv-R: 81.6%, AIME 2025: 81.2%.

Is Kimi K2.5 cheaper than GPT-5.5 Instant?

Kimi K2.5 is 8.3x cheaper for input tokens. Kimi K2.5 costs $0.60/M input and $3.00/M output via fireworks. GPT-5.5 Instant costs $5.00/M input and $30.00/M output via openai.

What are the context window sizes for Kimi K2.5 and GPT-5.5 Instant?

Kimi K2.5 supports 262K tokens and GPT-5.5 Instant supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Kimi K2.5 and GPT-5.5 Instant?

Key differences include context window (262K vs 400K), input pricing ($0.60 vs $5.00/M), licensing (MIT vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes Kimi K2.5 and GPT-5.5 Instant?

Kimi K2.5 is developed by Moonshot AI and GPT-5.5 Instant is developed by OpenAI.