GPT-5.5 Pro vs Kimi K2.6
GPT-5.5 Pro (OpenAI) and Kimi K2.6 (Moonshot AI) compared point by point: measured performance, pricing, context and capabilities.
Data as of October 22, 2026
Side-by-side comparison
| Criterion | GPT-5.5 Pro | Kimi K2.6 |
|---|---|---|
| Developer | OpenAI | Moonshot AI |
| Released | April 23, 2026 | April 20, 2026 |
| Capability index | 96.9 / 100 | 84.4 / 100 |
| Input price | $30 | $0.95 |
| Output price | $180 | $4 |
| Cost of a typical task | $0.96 | $0.027 |
| Context window | 1,050,000 tokens | 262,144 tokens |
| Maximum output | 100,000 tokens | 262,144 tokens |
| Reasoning mode | Yes | Yes |
| Tool calling | Yes | Yes |
| Accepted inputs | text, image, PDF | text, image, video |
| Open weights | No | Yes |
| Knowledge cutoff | December 1, 2025 | January 2025 |
What are we comparing?
GPT-5.5 Pro and Kimi K2.6 are the flagship models of two major developers, one from OpenAI, the other from Moonshot AI. GPT-5.5 Pro was released on April 23, 2026, Kimi K2.6 on April 20, 2026.
All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.
Which one is more capable?
On our capability index, GPT-5.5 Pro scores 96.9 out of 100 and Kimi K2.6 84.4. GPT-5.5 Pro leads by 12.5 points.
On the 3 benchmarks reported for both, GPT-5.5 Pro wins 3 times and Kimi K2.6 0:
- GPQA Diamond (PhD-level science questions): GPT-5.5 Pro 93.9%, Kimi K2.6 90.8%
- OTIS Mock AIME (competition mathematics problems): GPT-5.5 Pro 100%, Kimi K2.6 96.1%
- FrontierMath (very hard research-level mathematics): GPT-5.5 Pro 87.7%, Kimi K2.6 57.2%
Which one costs less?
GPT-5.5 Pro costs $30 per million input tokens and $180 per million output tokens; Kimi K2.6 costs $0.95 and $4.
For a typical agent task (read 20,000 tokens, write 2,000), expect $0.96 with GPT-5.5 Pro versus $0.027 with Kimi K2.6. Kimi K2.6 is 35.6 times cheaper, a gap that adds up quickly over 1,000 tasks: $933 difference.
Run the numbers with your own volumes in the agent cost calculator.
Under the hood
GPT-5.5 Pro reads more in one go: 1,050,000 tokens of context (roughly 1,575 pages), versus 262,144 for Kimi K2.6.
Reasoning mode: GPT-5.5 Pro yes, Kimi K2.6 yes. Tool calling: GPT-5.5 Pro yes, Kimi K2.6 yes. Image input: GPT-5.5 Pro yes, Kimi K2.6 yes.
Kimi K2.6 publishes its weights and can run on your servers; GPT-5.5 Pro is a closed model, available only through an API.
Knowledge cutoff: December 1, 2025 for GPT-5.5 Pro, January 2025 for Kimi K2.6.
In short
Our reading of the data:
- Choose GPT-5.5 Pro for a higher capability index and a larger context window.
- Choose Kimi K2.6 for a lower cost and open weights (you can host it yourself).
This verdict relies on public figures; it does not replace a trial on your own tasks.
Other comparisons
Frequently asked questions
GPT-5.5 Pro or Kimi K2.6: which is better?
On our index (Epoch AI data), GPT-5.5 Pro scores 96.9 and Kimi K2.6 84.4 out of 100. The best choice also depends on price and on your use case.
Which one is cheaper?
Kimi K2.6. To read 20,000 tokens and write 2,000, expect $0.96 with GPT-5.5 Pro and $0.027 with Kimi K2.6 (prices as of October 22, 2026).
Which one has the larger context window?
GPT-5.5 Pro, with 1,050,000 tokens versus 262,144.
Can I run GPT-5.5 Pro or Kimi K2.6 on my own servers?
Only Kimi K2.6, whose weights are published. GPT-5.5 Pro is used through an API.
Data sources
- Models.dev — Model data: models.dev (open-source project)
- OpenRouter — Market prices cross-checked with OpenRouter
- Epoch AI — AI Benchmarking Hub — Epoch AI, “AI Benchmarking Hub”, epoch.ai, CC BY 4.0
Data as of October 22, 2026
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