Model Comparison

GPT-5.5 vs Kimi K3Which is better in 2026?

Kimi K3 significantly outperforms across most benchmarks. Kimi K3 is 1.9x cheaper per token.

Verdict: GPT-5.5 vs Kimi K3 — which is better?

GPT-5.5 (by OpenAI) and Kimi K3 (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.

GPT-5.5 outperforms in 2 benchmarks (GPQA, MMMU-Pro), while Kimi K3 is better at 7 benchmarks (BrowseComp, FrontierSWE, GDPval-AA, Humanity's Last Exam, MCP Atlas, OfficeQA Pro, Toolathlon). Kimi K3 significantly outperforms across most benchmarks.

On price, Kimi K3 is roughly 1.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.5 also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose GPT-5.5 if…

  • you process long inputs — it offers a 1,050,000 token context window

Choose Kimi K3 if…

  • you want the strongest raw capability — it leads on 7 of 9 shared benchmarks
  • cost matters — it's about 1.9x cheaper per token
  • you want the most recent training data — it shipped Jul 2026

Performance Benchmarks

Comparative analysis across standard metrics

9 benchmarks

GPT-5.5 outperforms in 2 benchmarks (GPQA, MMMU-Pro), while Kimi K3 is better at 7 benchmarks (BrowseComp, FrontierSWE, GDPval-AA, Humanity's Last Exam, MCP Atlas, OfficeQA Pro, Toolathlon).

Kimi K3 significantly outperforms across most benchmarks.

Wed Jul 22 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Kimi K3 costs less

For input processing, GPT-5.5 ($5.00/1M tokens) is 1.7x more expensive than Kimi K3 ($3.00/1M tokens).

For output processing, GPT-5.5 ($30.00/1M tokens) is 2.0x more expensive than Kimi K3 ($15.00/1M tokens).

In conclusion, GPT-5.5 is more expensive than Kimi K3.*

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

Lowest available price from all providers
Wed Jul 22 2026 • llm-stats.com
OpenAI
GPT-5.5
Input tokens$5.00
Output tokens$30.00
Best providerOpenAI
Moonshot AI
Kimi K3
Input tokens$3.00
Output tokens$15.00
Best providerUnknown Organization
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.5 accepts 1,050,000 input tokens compared to Kimi K3's 1,048,576 tokens. Kimi K3 can generate longer responses up to 1,048,576 tokens, while GPT-5.5 is limited to 128,000 tokens.

OpenAI
GPT-5.5
Input1,050,000 tokens
Output128,000 tokens
Moonshot AI
Kimi K3
Input1,048,576 tokens
Output1,048,576 tokens
Wed Jul 22 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.5 and Kimi K3 support multimodal inputs.

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

GPT-5.5

Text
Images
Audio
Video

Kimi K3

Text
Images
Audio
Video

Release Timeline

When each model was launched

GPT-5.5 was released on 2026-04-23, while Kimi K3 was released on 2026-07-16.

Kimi K3 is 3 months newer than GPT-5.5.

GPT-5.5

Apr 23, 2026

2 months ago

Kimi K3

Jul 16, 2026

5 days ago

2mo newer

Knowledge Cutoff

When training data ends

GPT-5.5 has a documented knowledge cutoff of 2025-12-01, while Kimi K3's cutoff date is not specified.

We can confirm GPT-5.5's training data extends to 2025-12-01, but cannot make a direct comparison without Kimi K3's cutoff date.

GPT-5.5

Dec 2025

Kimi K3

—

Provider Availability

GPT-5.5 is available from OpenAI. Kimi K3 is available from Moonshot AI.

GPT-5.5

openai logo
OpenAI
Input Price:Input: $5.00/1MOutput Price:Output: $30.00/1M

Kimi K3

moonshot logo
Unknown Organization
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (1,050,000 tokens)
Higher GPQA score (93.6% vs 93.5%)
Higher MMMU-Pro score (83.2% vs 81.6%)
Moonshot AI
Less expensive input tokens
Less expensive output tokens
Has open weights
Higher BrowseComp score (91.2% vs 84.4%)
Higher FrontierSWE score (81.2% vs 73.0%)
Higher GDPval-AA score (55.6% vs 37.8%)
Higher Humanity's Last Exam score (56.0% vs 52.2%)
Higher MCP Atlas score (84.2% vs 75.3%)
Higher OfficeQA Pro score (63.3% vs 54.1%)
Higher Toolathlon score (73.2% vs 55.6%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-5.5 and Kimi K3 side-by-side, then vote on the output you prefer.

GPT-5.5
✓ Preferred
Kimi K3
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-5.5
Moonshot AI
Kimi K3

FAQ

Common questions about GPT-5.5 vs Kimi K3.

Which is better, GPT-5.5 or Kimi K3?

Kimi K3 significantly outperforms across most benchmarks. GPT-5.5 is made by OpenAI and Kimi K3 is made by Moonshot AI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT-5.5 compare to Kimi K3 in benchmarks?

GPT-5.5 scores Tau2 Telecom: 98.0%, ARC-AGI: 95.0%, GPQA: 93.6%, ARC-AGI v2: 85.0%, GDPval-MM: 84.9%. Kimi K3 scores MathVision: 97.8%, DeepSearchQA: 95.0%, GPQA: 93.5%, CharXiv-R: 91.3%, BrowseComp: 91.2%.

Is GPT-5.5 cheaper than Kimi K3?

Kimi K3 is 1.7x cheaper for input tokens. GPT-5.5 costs $5.00/M input and $30.00/M output via openai. Kimi K3 costs $3.00/M input and $15.00/M output via moonshot.

What are the context window sizes for GPT-5.5 and Kimi K3?

GPT-5.5 supports 1.1M tokens and Kimi K3 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.5 and Kimi K3?

Key differences include context window (1.1M vs 1.0M), input pricing ($5.00 vs $3.00/M), licensing (Proprietary vs Unknown). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.5 and Kimi K3?

GPT-5.5 is developed by OpenAI and Kimi K3 is developed by Moonshot AI.

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